Shortcrust Pastry
Blend flour, sugar, salt and half the butter in a bowl with a pastry cutter, or pulse in a food processor until the mixture resembles cornmeal. Add the rest of the butter and blend or pulse until pea-sized pieces remain.
Add egg and lemon juice and stir with a fork or pulse to combine.
Add one tbsp of water. Stir or pulse. Test if the pastry sticks together when pinched between the fingers. If not, add the second tablespoon of water.
Transfer dough to a lightly floured counter and form into a ball, then press into a disc. Cover and refrigerate for one hour.
Frangipane
Combine almonds and sugar in a food processor and pulse until they are the texture of coarse sand. Add butter and pulse until thoroughly combined.
Add eggs and almond extract and pulse until smooth and grainy. Transfer to a bowl with a lid and reserve.
Working with half the dough at a time, roll out on a counter lightly sprinkled with flour to a thickness of 1/4-inch. At first the dough will be crumbly, but don’t worry, it will come together as you roll.
Cut dough into 3 or 4-inch rounds and press lightly into muffin tins. *In my house, my biggest cutter is 3 inches, which makes 18 shallow tarts. A 4-inch round will give you 12 deeper tarts.
Chill in freezer for 10 minutes.
Preheat oven to 450F. Prick the base of each tart several times with a fork. Bake the tart shells for five minutes and remove from oven. If the bases have puffed up, press them down lightly with the back of a spoon. Cool to room temperature.
Reduce oven temperature to 375F.
Spoon 2 tsps (for shallower tarts) to 1 tbsp raspberry jam (for deeper tarts) into each tart shell. Spoon enough almond mixture over top to cover the jam, from 1 to 1 1/2 tablespoons. You will have plenty of frangipane left for the next batch of tarts!
Bake for 15 to 18 minutes, until tops are golden brown.
Serve at room temperature—the crust will be crisp and the filling both smooth and just slightly crunchy.