Fresh Strawberry Buttersponge with Mascarpone Mousse and Strawberry Sherbet

MAKES A 20 CM (8 IN) CAKE FOR 8–12. 

Takes 1 hour to make, bake and cool the sponge. Just over 1 hour to make the mousse and assemble. Chill at least 4 hours, but ideally overnight. 

Keeps Up to 3 days. 

It will be completely un-shocking that my visit to Japan was more cake-centric, less fish-focused. I ate the flooffiest pumpkin doughnuts, elegant apple shortbread cookie sandwiches, silky coffee caramel flan and cheesecake. At the tiny pastry shop Equal Pastryshop, I ate a strawberry shortcake whose perfection made me want to hang up my apron, because if such baking beauty already exists in this world, then my efforts are futile. 

The Japanese shortcake is their refined version of the American shortcake and is layers of dairy-rich sponge, cream and strawberries. Eating it feels like hugging a puppy, the first day of t-shirt weather in spring and knowing you are loved all at once.

This isn’t the greatest cake in the world. Equal makes that. This is just a tribute.

INGREDIENTS:

• cooking oil spray

Buttersponge cake

• 100 g (3½ oz) unsalted butter

• finely grated zest of 1 lemon

• 130 g/ml (4½ oz) full-cream (whole) milk

  Beatrix Bakes Another Slice Natalie Paull

• 80 g (2¾ oz) egg yolk (from approx. 4 eggs) + 240 g

• (8½ oz) egg whites (from approx. 8 eggs)

• 10 g (¼ oz/1 teaspoon) vanilla paste

• 150 g (5½ oz) self-raising flour (OR 145 g/5 oz soft plain/ all-purpose flour + 7 g/1/4 oz baking powder)

• 2 g (1/16 oz/1/4 teaspoon) salt

• 3 g (¹⁄₁₀ oz/heaped 1/4 teaspoon) cream of tartar

• 170 g (6 oz) caster (superfine) sugar

Filling

• 1 × batch White chocolate and mascarpone mousse–start this after the sponge is baked so the gelatine is still flexible

• 160 g (5½ oz) strawberry jam (homemade or very good store-bought)

• 750 g (1 lb 11 oz) fresh, perfectly ripe strawberries

Strawberry sherbet dust

• 20 g (¾ oz) icing (confectioners’) sugar

• 5 g (1/8 oz) freeze-dried strawberries

• 2 g (1/16 oz/1/4 teaspoon) citric acid

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ADAPTRIX:

Fig

When perfect figs are available, make this! You’ll need around a kilo (2 lb 3 oz) of small figs. Prepare the figs by rinsing them and then nicking off the stem tip. Set aside any imperfect ones for the jam. Finely chop 150 g (51/2 oz) of the figs with a splash of vincotto and 30 g (1 oz) caster (superfine) sugar and simmer to a jammy consistency. Set aside to cool. Make the White chocolate and mascarpone mousse (page 257) – Adaptrix scented with fig leaf – it’s amazing! 

When assembling, place the whole figs in the same hearts top to tail concentric circle formation. Fill in the remaining mousse and top with the second fig jam–slicked sponge layer. Dust with freeze-dried raspberry sherbet. 

Just mascarpone + classic shortcake

You can skip the white chocolate mouse and use 750 g (1 lb 11 oz) mascarpone whipped with 250 g/ml (9 oz) cream (35% milkfat) to medium peaks. Layer into the tin as above, but you’ll need to give the tin a few firm raps on the counter to settle the thicker cream. Chill for an hour, unmould, then whip a little extra cream to completely cover the top and side of the cake. Quarter some extra strawberries with their green tops on and arrange, gently pushing each quarter into the cream top at spaced intervals around the perimeter. 

Raspberries/blackberries

If using raspberries, place them pointy-side up to get extra presence in the deep mousse layer. Don’t over pack so the fruit pieces are against each other with no cream in between. Match the fruit with the jam – store-bought is okay … just give it an acidic tszuj with a few drops of lemon juice.

Square up

I adore this cake as a sharp-angled square. If you have a deep 20 cm (8 in) square tin, cut the sponge into two snug-fitting squares, line the tin as above and assemble. Cut into bars 10 cm × 5 cm (4 in × 2 in). 

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PREPARATION: 

Heat the oven to 140°C (285°F). Lightly spray a 40 cm × 30 cm × 2 cm (153/4 in × 12 in × 3/4 in) deep tin with cooking oil and line with one sheet of baking paper. It’s okay if the long tray sides are exposed. Keep the short side paper flush with the tin edge. Trim flappy paper – the enemy of smooth cake tops everywhere. 

Leaving the paper un-sprayed will pull the bottom crust away – a good and deliberate thing for this blond layered cake. If you want the crust, spray the paper after lining the tin.

Place the butter and lemon zest in a small saucepan over a medium–high heat and cook until the butter is sunshine yellow with white milk solids on the base. When cooked, pour the yellow butter into a wide mixing bowl, leaving the white solids behind, and immediately add the milk to cool the mixture down quickly. Hand whisk in the egg yolks and vanilla. 

Weigh the flour and salt into a small bowl and set aside with a sieve on top.

Put the egg white and cream of tartar in the bowl of an electric stand mixer. Using the whisk attachment, whip on speed 6 (medium–high) for 1–2 minutes, until the whites have changed from foamy to stiff and white. 

Start adding the sugar to the whites very gradually – about 1 heaped teaspoon every 20 seconds, so the whole process takes 3–4 minutes. It is imperative to the success of the cake that the meringue is so stiff you could carve a knife through it. After all the sugar is in, reduce to speed 1 (low) for 1 minute to even out the air bubbles. 

While the meringue does the slow whip, sift the dry ingredients over the butter/milk/yolk mix and whisk in by hand to make a smooth paste, then gently and thoroughly fold in one-third of the meringue. The super-stiff meringue will be hard to blend at first – just keep folding, shaking the batter off the whisk from time to time. Gently fold in the remaining meringue and do a final fold with a plastic spatula until no white streaks remain. Scrape the mixture into the tin and smooth the top, making a recessed rectangle with a 2 cm (3/4 in) border – think photo frame. 

The recess controls doming so you achieve an even and flat sponge. 

Bake for 15–18 minutes until the top is pale gold. While the cake bakes, set up a cooling rack on your work surface and spray it with cooking oil. As soon as the cake is done, quickly run a knife along the unpapered sides and confidently flip the cake from the tin onto the cooling rack. If you flip slowly, the cake can get squished ortear.* Gently peel away the paper and set the rack over your sink (or carefully elevate) to get maximum cooling airflow beneath. 

While the cake cools, start the White chocolate and mascarpone mousse so it is still pourable when you reach assembly time. If the mousse sets, you can still assemble but the sides won’t be as smooth. 

To assemble

Time the mousse making so it is still pourable (not scoopable) when assembling. Lightly spray a 20 cm (8 in) round × 7.5 cm (3 in) deep cake tin with cooking oil, then line the base and sides with baking paper. 

Flip the sponge sheet onto the work surface and cut two 19 cm (7 1/2 in) diameter circles with a small, sharp knife. Don’t fret if you are right on the edge of the sponge – the mousse will hide any rough edges. Snack on the offcuts.

I have a 19 cm (7 1/2 in) pot lid I use as a guide to cut around. 

Divide the jam between the two sponge circles and spread out over each top. Place one circle in the lined tin, jam side up, so it sits with an equal gap around the circumference. Pour half the mousse in and smooth out. Place the fresh strawberries in on their sides in concentric circles – pointy end against wide top – imagine hearts top to tail. 

This particular placement means that every slice will have that perfect cross section. 

Pour the rest of the mousse on top and shimmy with the tip of your spatula to ensure it settles around the strawberry nooks and crannies. Flip the second sponge circle on top, jam-side down – slide the top sponge if it needs centering. 

Don’t worry if it looks messy. It will turn out neater than you think! 

Cover the top with plastic wrap. Sit a tart tin base on top and pop around 500 g (1 lb 2 oz) of weight on top (equivalent to two blocks of butter). Chill for at least 4 hours before unmoulding, but overnight is best. 

Make the sherbet by whizzing the icing sugar, freeze-dried strawberries and citric acid in a spice grinder or food processor.

Just before serving, peel the plastic wrap back to expose the cake top. Place the serving platter on top, then invert onto the serving platter. Remove the tin and gently peel away the paper. Sift a snowdrift of sherbet dust over the top. 

Dust just before serving. The sherbet dust will liquefy a little when chilled and uncovered.  

* If this fragile cake tears or squishes, don’t worry – you can patch the cake in and it will set and slice like a dream.

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WHITE CHOCOLATE AND MASCARPONE MOUSSE MAKES JUST OVER 900 G (2 LB).

Takes 1 hour to prepare. 

Keeps: Use within 4 days (it will tighten as the gelatine ages). Can be frozen for up to 3 months and defrosted in the fridge. It will be softer upon defrosting, so don’t rely on it to hold up structurally like the fresh made mousse.

This is an easy, eggless mousse, plumped up with mascarpone for density and that gentle lactic tang. It works so well in the Fresh strawberry buttersponge cake (page 188). Even if you aren’t making cake, this mousse is a perfect party finisher set in little bowls and topped with berries or passionfruit. 

INGREDIENTS:

• 200 g (7 oz) good white chocolate, in small buttons or chopped finely

• 250 g (9 oz) mascarpone

• 350 g/ml (12½ oz) cream (35% milkfat)

• 8 g (¼ oz) titanium strength gelatine leaves (or 4 g/1/8 oz gold strength gelatine leaves) + cold water

• 150 g/ml (5½ oz) full-cream (whole) milk

• 5 g (1/8 oz/½ teaspoon) vanilla paste

• teeny pinch of fine sea salt

PREPARATION: 

Weigh the chocolate into a wide heatproof bowl and set aside. Stir (or hand whip) the mascarpone and cream to slumpy soft peaks and keep chilled for later.

Mascarpone thicknesses can vary and will dictate the amount of whipping required.

Soften the gelatine leaves in enough cold water to just cover them, and leave until the gelatine feels like soggy cling wrap. While it softens, heat the milk, vanilla and salt in a small saucepan until you get a bubbly boil across the entire surface. 

Try to have the milk and gelatine ready at the same time. If the gelatine softens quickly, squeeze it out and let it rest in a clean bowl, ready for the hot milk. Oversoaked gelatine leaves dissolve and lose setting efficacy. 

As soon as the milk boils, squeeze the water from the gelatine and whisk into the milk, then immediately scrape the hot milk onto the chocolate. Let it sit for 10 seconds, then give it a good whisk to dissolve the chocolate. 

If the chocolate hasn’t melted, make a double boiler with the milk saucepan and gently warm the mix to melt any stubborn chocolate pieces. 

Cool the mix at room temperature to around 25–28°C (75–80°F). Every 5 minutes or so, gently whisk and scrape down the side of the bowl with a flexible plastic spatula. Do this until the mix begins to set. This should take around 10–20 minutes – less time in colder weather.

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Excerpted with permission from Beatrix Bakes: Another Slice by: Natalie Paull published by ‎Hardie Grant Publishing, April 2024, RRP $35.00 Hardcover.

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