First, make the frangipane. Cream together the butter and sugar until light and fluffy and almost white in colour. Beat in the eggs one at a time – if the mixture looks like it is going to separate, add a little flour. Fold in the rest of the flour along with the almonds and salt, then store in the fridge for up to a week. Allow it to come to room temperature before using.
Preheat the oven to 170°C. Gently spread the jam over the bottom of the tart case. Fill a piping bag with the frangipane (you’ll need about 350g for this recipe) and pipe it over the jam, up to the pastry lip. Push the raspberries into the frangipane.
Bake in the oven for 8 minutes, then sprinkle over the flaked almonds and bake for another 20 minutes. Use a skewer to check the centre of the tart – if it comes out clean it’s cooked, otherwise give it another 5 minutes. Leave to rest for at least 1 hour before serving with crème fraîche.