Coffee Tiramisu without Alcohol

Stir the instant coffee and 1 tbsp sugar into the hot water until dissolved. Pour into a shallow bowl and leave to cool completely.

Put the egg yolks, 100 g caster sugar and milk in a heatproof bowl. Set it over a saucepan of barely simmering water, making sure the base of the bowl does not touch the water.

Whisk constantly for 8–10 minutes until the custard is pale, thick and coats the back of a spoon. It should reach 72°C, which cooks the yolks safely.

Lift the bowl off the heat and whisk for a minute. Let the custard cool to room temperature for about 10 minutes, whisking now and then so no skin forms.

In a large bowl, beat the cold mascarpone and vanilla with a spatula or on low speed until just smooth. Do not overbeat or it can turn grainy.

Fold the cooled custard into the mascarpone until combined and glossy.

In a separate bowl, whip the cold cream to firm, soft peaks. Fold it into the mascarpone mixture in two additions, keeping as much air as you can.

Dip each ladyfinger into the coffee for 1–2 seconds per side. It should be damp but still hold its shape. Arrange half of them in a single tight layer in the dish.

Spread half the cream mixture over the biscuits and level it. Dip and add a second layer of biscuits, then top with the remaining cream and smooth the surface.

Cover and chill for at least 6 hours, or overnight, until the tiramisu is firm enough to cut into clean squares.

Just before serving, dust the top with cocoa through a fine sieve and scatter over the grated chocolate, if using. Cut with a sharp knife dipped in hot water.