Prepare the tartlets. Combine the butter at room temperature, water, salt and flour, and knead the dough.
Roll out the dough into a layer, cut out circles in the shape of muffin molds, put them inside, flatten.
Bake in the oven at 200°C for 15 minutes. Then allow to cool completely and remove the tartlets from the molds.
For the filling, mix the ricotta, dill, lemon juice, salt and pepper. Cut the cucumber into slices.
Put the filling in tartlets and garnish with cucumber slices.