First we are going to make the dough for the tartlets. If you have a mixer you can use it, but the good thing about this recipe is that it can be done perfectly by hand. In a large bowl we mix 190 grams of wheat flour with a pinch of salt and, with the help of a spatula, we mix it with 100 grams of butter, at room temperature, until there is a dough divided into small pieces the size of a pea .
In a separate bowl, mix 60 ml of cold water, an egg yolk and a teaspoon of white vinegar. We beat it well and add it to the large bowl with the dough. With the help of a fork we combine everything. We can add one more tablespoon of water if the dough seems too dry. Mix the dough well and form a griddle. Cover it with plastic wrap and let it settle in the fridge for at least 30 minutes.
Once the dough is refrigerated, form a rectangle of approximately 40 x 30 cm and about 4 millimeters wide. Always work with flour on the table so it does not stick. Now, using a circular cutter of about 10 cm in diameter, make as many circles as you can with the dough. What is left over can be put together to make a new plate and make more circles, but it is important to work quickly so that the dough does not get too hot. Now, with your hand, put these circles on a muffin tin, to form the base of the tartlets. Refrigerate again while you make the filling. It is now when we can turn on the oven so that it warms up to 220º C.
Meanwhile, if you are going to use raisins, cover them with hot tap water to hydrate them a bit. In a bowl, mix 220 grams of brown sugar, half a teaspoon of salt and the remaining 60 grams of butter. Then add a teaspoon of vanilla extract and an egg and mix everything by hand with a fork or whisk. Better by hand, not with a mixer, because if we don’t put a lot of air into the mix.
Take the tartlets out of the fridge and fill them halfway (because they are going to increase a bit in volume). Bake for about 15 minutes for juicier tartlets and up to 20 minutes for firmer tartlets. They are all good, but surely you will get the point that you like the most.
After removing from the oven, separate the tarts from the pan a bit with a buttered knife, but allow them to cool completely to unmold them.