Cut up cold butter into the flour and knead until you obtain small crumbles. Add water and salt and knead until you get a homogenous mass. Dust with flour, form a ball, wrap it with plastic wrap and let it rest in the fridge for at least two hours.
Butter a pan 15cm Ø, 6cm high. Put a little flour on the working surface and roll out the dough. Carefully put it into the pan and press down evenly with your hands. Put it back into the fridge for another 10 minutes.
Put parchment paper on top of the dough in the pan and with the aid of beans or lentils blind-bake for about 40 minutes at 180°C top and bottom heat.
In the meantime finely chop the shallots and sweat with a little piece of butter in a pot. Add the frozen peas and simmer for 5 minutes.
Finely chop mint, thyme and dill and mix with the peas. Put onto the pre-baked dough.
Puree mascarpone, cream, eggs, roquette, parsley, salt, pepper and nutmeg in a blender. Disperse over the peas.
Bake the tart at 190°C for about 45-50 minutes. Serve with a fresh salad.