In a bowl or using a standing mixer, start slowly mixing the flour, the baking powder, the lemon zest and the butter.
Add the sugar...
... the eggs..
... and the milk.
Adding the milk slowly, you will obtain the desired texture.
The final result is a rich shortcrust pastry, that you will wrap in plastic film. Put it into the fridge, where it will rest (minimum 1 hour, ideally 3-4 hours).
After the resting period, roll it with a rolling pin and cut circles with the mold. Turn on the oven at 170 °C.
Put at the centre of each circle a teaspoon of mustard, then close the shapes creating the raviole. Press the borders so they don't open while cooking.
Place the raviole on a baking tray covered with baking paper. With a finger, moist the top with some milk, spray with some sugar and put them into the oven.
After 20 minutes, the raviole are ready! PRO TIP: you can moist the raviole with some alkermes liquor, with its typical dark pink color. Amazing! :)