Combine the flour, ground almonds, cinnamon and salt in a mixing bowl. Rub in the diced butter by hand until the mixture resembles coarse breadcrumbs. Rub in the marzipan, taking less care to break it down – some larger pieces can remain. Stir in 50g of the muscovado sugar with the crumbled amaretti biscuits, flaked almonds and lemon zest.

Alternatively, pulse the flour, ground almonds, cinnamon, salt and butter together in the small bowl of a food processor, adding 50g sugar for a final few pulses once the mixture resembles coarse breadcrumbs and stirring in the marzipan, amaretti, flaked almonds and lemon zest at the end. Either way, cover and chill the crumble mix for 20 minutes. To get ahead, the crumble mix can chill for up to 2 days, and it also freezes well for up to three months.

Preheat the oven to 170°C/Fan 150°C/Gas Mark 3. Combine the apples with the lemon juice to prevent browning. Tumble in the remaining muscovado sugar, distributing the two apple types evenly. Transfer to a medium-sized baking dish about 23cm diameter if round or about 20x25cm if not. Scatter the crumble over the fruit to cover completely.

Bake in the preheated oven for about 1 hour 10 minutes until golden, crisp and bubbling at the edges.

To flavour the custard, put it in a blender with the chopped marzipan and the Amaretto. Blend for a couple of minutes (this needs to be thorough), then, if your blender isn’t supercharged, pass through a sieve to remove any small marzipan pieces. 

Leave the crumble to settle for 10 minutes before serving with the marzipan custard (gently warmed through or cold) and vanilla ice cream, or with chilled Greek yoghurt as a simpler option.

Recipe extracted from Repertoire: The Best Vegetarian Recipes to Build a Modern Cook’s Collection by Alice Hart, published by OH Editions, priced £27, with photography by Emma Lee.