This dessert sounds and possibly looks complicated, but it isn't at all! It's just a simple sweet pastry layer topped with lemon curd and almond frangipane layers. Lemon bakewell slices are a traditional British dessert with a lemon twist.... enjoy!
In a large bowl, quickly rub the butter into the flour with your fingertips until it resembles fine breadcrumbs.
Stir in the icing sugar and lemon zest, then add the egg yolk and tablespoon of water. Mix lightly then bring the dough together with your hands. Wrap in plastic wrap and chill for at least half an hour.
Pre-heat the oven to 350F/180C. Line a baking tin (about 20x20 cm or 8x8 inches) with baking paper and grease it well with a little butter.
When the pastry has chilled, roll it out so that it's a little bigger than the baking tin. Then place the baking tin on top of it and cut around it with a sharp knife. Use this square of pastry to line the bottom of your tin, making sure you push it right into the corners. Bake for 10 minutes.
Meanwhile, make your filling. Beat together the butter, sugar and lemon zest with a handheld whisk until light and creamy-looking. Gradually add the eggs and ground almonds, then stir in any remaining ground almonds and the flour.
Roughly spread the lemon curd over the pastry base (don’t go right to the edge, to stop the curd layer from sticking to the baking paper while cooking). Then top with the almond filling and smooth down with a spatula or the back of a metal spoon.
Scatter over the flaked almonds, then bake for 15 to 20 minutes, until the top of the dessert is lightly golden.
Cut into 8 slices, then serve warm with ice cream, custard or cream or cold, by itself.
Pastry: Use cold ingredients and handle as little as possible. The dough might be quite soft and sticky, but it'll be easier to roll out after chilling. If it breaks up while pressing into the cake pan, just patch it up and smooth it over. It'll be fine! I usually make the pastry by hand, but you can also make it in a food processor. Again, don't overmix. Pulse just until a pastry ball forms. Frangipane layer: Don't overmix. Just mix until well combined for the lightest, fluffiest result.