Photo: Laura Edwards
First, make the jam. Put the cherries in a pan, add the lemon verbena leaves and lemon juice and cook slowly for about 20–25 minutes until the cherries have broken down. Pour into a jug and measure how much juice you have. You want to add about three-quarters of the amount you have in sugar. Tip the fruit and juice back into the pan, add the sugar and gently heat to dissolve the sugar, then bring to the boil. Cook hard until you reach the setting point – this could be as little as 10 minutes. Have a plate in the freezer and when the bubbles start to get slow and sluggish, it is time to test.
Spoon a little of the jam onto the cold plate and push it with your finger. If it wrinkles, then it is ready; if not, then cook for 5 more minutes and test again. Alternatively, you can use a sugar thermometer and take the jam off the heat when the temperature reaches 105°C, 221°F. When the jam is ready, pour it into a bowl and set aside to cool completely.
For the pastry, beat the butter and sugar together until really creamy and fluffy. Beat in the egg and egg yolk, then add the flour and baking powder. Bring together to a dough and knead briefly until smooth, then shape into a disc and chill for 30 minutes. For the filling, heat the milk in a pan with the vanilla pod and seeds until almost boiling. Beat the egg yolks and sugar together until fluffy, then add the flours and beat until smooth. Pour over the milk and mix together, then return to the pan over a low heat and cook until you have a very thick, smooth mixture. Spoon into a bowl, cover with cling film (plastic wrap) and leave to cool completely.
Cut off a piece of pastry about 50g in weight to use to make the lauburu (Basque cross). Divide the rest of the pastry into a third and two-thirds. Roll out the bigger bit and use to line the base and sides of a 25 cm deep, loose-bottomed cake tin. Spoon the cold cream filling into the tin, then dot spoonfuls of the jam over the top. Roll out the smaller piece of pastry and cover the jam, trimming away any excess and crimping the sides of the pastry together.
Roll out the last bit of pastry and cut out the Basque cross (you may want to make a template to help you). Brush the top of the pastry with the beaten egg, top with the cross, then glaze again. Chill while you heat the oven to 180°C, fan 160°C, Gas 4.
Bake the pie for 35–45 minutes until golden brown. Leave to cool in the tin before releasing and serving.
Basque: Spanish Recipes From San Sebastián And Beyond by José Pizarro (Hardie Grant, £25)