You can find mulberry jam at most good delicatessens and supermarkets. Tiptree Jam make jam from their own mulberries. Believe me, it is the best mulberry jam I've ever tried and it's a completely British product. Preheat the oven to a medium heat - 300-350 degrees F (150-180 degrees F). Mix the flour with the butter and add the lemon zest. Divide the dough into two and place in the refrigerator until cold. Roll out one quantity of dough on a cold surface and line a flan case with it. Place this in the refrigerator, together with the remaining quantity of dough, which will be used later for the lid.

Using a large bowl, combine the soured cream and the pecan nuts. Scrape the seeds out of the vanilla pods and add them to the bowl. Add the ground nutmeg, almond extract, cinnamon and egg yolks. Mix all the ingredients together.

Remove the pastry-lined flan case from the refrigerator. Gently spread the jam over the entire surface of the bottom of the flan case. Then spread the pecan and soured cream mixture on top of this. Place the flan case to one side.

Roll out the other piece of pastry on a cold surface. Place it on top of the flan to make a lid; trim the edges. Put the pie in the oven and bake for about 45 minutes until golden brown and slightly puffy.

You may want to whip up some double cream to serve with this. It's great both hot and cold.