On my mother's side, I have Basque ancestors--and this is the classic cake from their region, masterfully interpreted by my (non-Basque!)husband David Leach.
(serves 4-6 people)
Ingredients for pastry: 200g plain flour, 1 whole egg plus 1 egg yolk, 130 g castor sugar, 130 g unsalted butter, pinch salt, lemon rind. Ingredients for custard: 200 ml milk, 1 egg yolk, 50 g castor sugar, 20 g plain flour, a little cherry brandy(optional), some stoned Morello cherries(he used our own homegrown ones which had been preserved in armagnac but tinned Morellos could conceivably be used). First make the pastry: put the flour in a bowl, make a well in it and into it put the egg yolk, the lightly beaten whole egg , the sugar, pinch salt, and the softened butter. Mix carefully till well combined and forming a good smooth and not sticky pastry. Put it in the fridge to rest while you prepare the custard. Dilute the flour with a little of the milk. Warm the rest of the milk gently. Beat the egg yolk with the sugar, then add to warmed milk, and then add the flour mixture, stir over stove till nice and thick(and do not let it boil.) Off the stove, add a little cherry brandy, and then the cherries. If you want to make the classic custard-filled Gateau Basque, omit both the cherries and cherry brandy. You can also flavour your custard with rum if you like.
Grease a cake or tart tin, roll out the pastry, make a base and sides out of most of it, then pour the custard mixture into it. Make a lid with rest of the pastry, crimp the edges well together, then glaze the top with a pastry brush dipped into some egg yolk. Score the pastry with a knife to form a pattern. Bake in a moderate oven for about half an hour. The cake is delicious both warm and cold.
Etorri mahaira! (Come to the table!)