For the shortcrust pastry, put the flour in a large bowl and press a depression in the middle. Add sugar, egg, 150 g butter, oil and lemon zest. First mix the wet ingredients with a fork to a compact mass.
Then quickly knead everything into a smooth dough with your hands. The dough should feel like "kneading" - if it is too dry, some more oil, if it is too fat, knead in some more flour. Cover the dough and put it in a cool place for about 30 minutes.
For the cream, mix the ricotta, sugar, eggs, lemon juice and zest in a bowl with the whisks of the mixer.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Grease the recesses of a muffin tray (12 troughs) with butter. Divide short pastry into 12 portions and form into balls.
Press each ball of dough flat and line the baking troughs with it, pulling the rim up slightly and pressing it down.
Fill the tartlets with ricotta cream too little 3⁄4 Bake in the oven for 18-20 minutes until the ricotta cream is lightly curdled and the dough is golden brown. Let the tartlets cool down.
Just before serving, wash and clean the fruit and cut it into small pieces. Place them on the ricotta tartlets. Dust with icing sugar.