You can buy pistachio paste from Sous Chef.
Heat oven to 160C/140C fan/ gas 3. First, make a frangipane. Beat the sugar and butter until light and fluffy, then beat in the eggs one at a time. Add the pistachio paste, flour and almonds and mix well.
Spread the black cherry jam over the base of the pastry case, top with the frangipane mixture and bake for 25-30 mins. Leave to cool completely, then serve with crème fraîche, if you like.