Strawberry cake with sponge and diplomat cream

Get water warming on the stove for a bain-marie. The sponge pan is left ungreased and unlined.

Crack six whole eggs into a bowl and whisk in the sugar and a pinch of salt.

Whisk over the bain-marie by hand until the eggs reach 113F and the mixture has about doubled in volume.

Transfer to a stand mixer with the whisk attachment and beat, increasing gradually from medium-low, until very thick and ribbony and it falls slowly off the whisk.

Sift the flour over in thirds and fold it through with a skimmer.

Stream in the melted butter lightly and fold it through, then add the vanilla and fold until well mixed. Some deflating is normal.

Scrape all the batter into the pan, centre the baking core, tap the pan on the counter several times to pop the large bubbles and smooth the surface.

Bake at 350F for 25 to 30 minutes, until the top is very golden brown, risen and springy. This one took almost 29 minutes.

Sprinkle the gelatin over two tablespoons of cold water to hydrate.

Warm the milk with a glug of vanilla paste, a pinch of salt and about half the sugar.

Whisk the egg yolks with the cornstarch and the other half of the sugar until pale and slightly thick.

Stream about two thirds of the warm milk into the yolks to temper them, then whisk the whole thing back into the pan.

Whisk constantly over the heat until it comes to a boil, holds the marks of the whisk and the foam disappears, then cook a good 20 more seconds to cook out the starch.

Off the heat, whisk in the hydrated gelatin until smooth, then whisk in the butter.

Cool the pastry cream over an ice bath in a metal bowl, stirring, until fridge cold.

Invert the sponge onto a rack immediately and cool it upside down.

Hull the strawberries. Chop just under a pound for the filling and slice the nicer half lengthwise for the decoration.

Toss the chopped strawberries with a squeeze of lemon, a little Grand Marnier, a little sugar and a little vanilla and leave them to macerate.

Whip the cup of heavy cream to between medium and firm peaks and fold it into the cold pastry cream until there are no streaks.

Wash the pan and leave it wet, then line it with plastic wrap, which clings to the wet surface, smoothing the bottom and up the sides.

Shave the thinnest possible layer off the top of the sponge to expose the crumb, then split it into two layers about half to three quarters of an inch thick, and peel the skin off the bottom.

Trim about a quarter inch off the edge of each layer all the way around to leave a gap for the strawberry layer.

Lay sliced strawberries over the bottom of the pan and one layer up the sides, cut side out, no overlapping and minimal gaps.

Dollop about a cup of the filling into the centre and spread it over the strawberries with the back of a spoon, pushing it into the gaps, then work a little up the sides.

Press in the first sponge layer, then build the second layer of strawberries up the sides.

Drizzle some of the macerating juices over the sponge, add a thin layer of cream, then the macerated berries in an even layer.

Add another layer of filling, complete the strawberry perimeter to the very top and work more cream up the sides.

Soak the second cake layer with the remaining juices and press it in soaked side down.

Finish with a very thin layer of filling over the top to seal, press it into the sides and cover with plastic.

Chill at least 12 hours so the gelatin sets, then push the removable bottom out and slice with a sharp serrated knife.