Preheat the oven to 180˚C (350˚F). Reduce by 20˚C/70˚F if yours is a fan oven.

Break the white chocolate up into little pieces and place in a microwaveable bowl. Microwave the white chocolate at 50% power for 60 seconds, stir, and give it another 30 - 45 seconds. Stir until it's all melted. Set aside.

Mix the cornflour into the almonds.

Beat the egg whites with 2 tablespoons of sugar, until stiff. Set aside.

With the same beaters, beat the butter and the rest of the sugar on medium for 1 minute, until pale.

Add the yolks, one at a time, beating about 30 seconds before each yolk, still on medium speed.

Then add the lemon zest, almonds, white chocolate and limoncello. Fold in with a rubber spatula or wooden spoon.

Now, using the same spatula, fold in the stiff egg whites in 3 additions, using a light hand, in an east-west, north-south direction. No stirring round and round.

Bake in the preheated oven for 45 - 50 minutes, until the sides are just coming away slightly and a cake tester comes out dry.

Leave to cool, then serve as you fancy. Keeps for 2 days, in a tightly sealed container.