Preheat oven to 200ºC/400F. Lightly grease a loose bottomed tart/flan tin with butter.
Line the greased tart tin with the ready rolled shortcrust pastry. Line the bottom with baking paper then weigh it down with baking beans or dried rice.
Bake for about 12 minutes or until golden. Remove the paper and baking beans and cook the tart for a further 5 minutes.
Meanwhile, make the frangipane filling. Cream the butter and sugar together until fluffy, then beat in the eggs, one at a time, then add the almond extract. Gently fold in the ground almonds.
Spread the raspberry jam over the base of the part-cooked tart, then pour in the frangipane filling and spread to make it level. Bake for 25 minutes or until golden.
For the icing, mix the icing sugar, water and raspberry jam until smooth, then drizzle over the bakewell tart. Decorate with the fresh raspberries.