Make the shortcrust pastry following the instructions on page 235 of Regula’s book, or another book if you like, or use store-bought, there is no shame in it.
Prepare the cake tin. Roll out the pastry on a floured work surface to a thickness of 5 mm. Fold in the sides so that the pastry will fit into the base of the baking tin, then gently lift it into the tin, letting it sink down into the base.
Use a small piece of excess dough to firmly press the edges of the pastry into the tin. Trim the excess pastry with a knife and then pierce the base with a fork. Put the pastry in the fridge to rest for at least 30 minutes or overnight (we don’t blind-bake this pastry as we want it to blend a little with the filling).
Blanch the apricot kernels in boiling water, then remove the skins. Using a mortar and pestle, bash the apricot kernels with the rosewater to make a paste.
Melt butter in a saucepan but don’t let it bubble. Remove the pan from the heat, add the sugar, almond meal, apricot kernel paste and breadcrumbs and stir well.
Add the eggs and nutmeg and mix well. Let the filling rest for at least one hour. Towards the end of the resting time, preheat the oven to 200C (no fan heat!).
Spread the jam over the pastry base and spoon the filling on top. Sprinkle with the flaked almonds and bake for 30-35 minutes until golden brown.