First, make the sponge. Butter a 20cm cake tin and line with baking parchment. Blitz the pistachios in a small blender until chopped to a fine texture similar to ground almonds. Be careful not to over-process or the oils will release and create a paste. Heat the oven to 180C/160C fan/gas 4.

Beat the butter and sugar together in a bowl using an electric whisk, then whisk in the eggs, one at a time. Fold in the flour, milk and ground pistachios, then spoon into the tin and smooth the surface using a spatula. Bake for 20 mins until the sponge is golden and springs back when pressed. Cool on a wire rack.

Bring the ice cream out the freezer to soften for 10 mins and double-line a medium glass bowl with strips of baking parchment, leaving some overhanging. Scoop in the ice cream and press down using the back of a spoon and smoothing the surface. Return to the freezer.

When the sponge has cooled fully, trim it so that it will fit on top of the ice cream later. Use the bowl as a guide, then return it to the freezer.

For the meringue, beat the egg whites to soft peaks using an electric whisk, then add the sugar, 1 tbsp at a time, whisking between each addition until it reaches stiff peaks. Whisk in the lemon juice or vinegar.

You will need to assemble the alaska quickly to prevent the ice cream melting, so have a kitchen blowtorch, spatula, the compote and the sponge ready when you take the bowl of ice cream out of the freezer. Spread the compote over the ice cream, then press on the sponge. Invert onto a serving plate or tray so the sponge is now on the bottom, using the parchment to help turn it out. Remove the parchment.

Dollop on the meringue, spreading and swirling it down the side using a spatula until the ice cream is fully covered. Blowtorch the meringue all over until golden (see tip, below). Scatter over the pistachio nibs. Serve immediately.