Put the flour, chopped cold butter, salt and water (add this little by little) in a mixer with a paddle attachment and knead until you get an elastic dough.

Make a ball, wrap it in cling paper and put it in the fridge for at least 40 minutes.

Mix the cream with the vegetable stock, warm them for 40 seconds in the microwave and keep them aside.

Put the butter in a non stick pot and let it melt.

Add the flour and whisk constantly until well incorporated.

Now start adding the vegetable stock and cream little by little, while mixing continuously. Do not add the next batch until the liquid is well incorporated.

Cook for 5 minutes then put the fire off.

Season with salt, pepper and nutmeg.

Add 4 tbsp of the grated Parmigiano Reggiano and egg yolks and mix well until incorporated and smooth. Keep aside.

Take the dough out of the fridge, place it on a sheet of baking paper and roll it into a 3 mm – 0.12 inch thick sheet.

Cut 6 circles of approximately the same size as your tart tins and put the dough in the greased tins. Press it down well and make sure you have dough at the sides as well.

Prick the dough with a fork and fill the tarts with the Parmigiano Reggiano mixture.

Sprinkle with the remaining grated Parmigiano Reggiano and bake them in a pre-heated oven at 190°C – 375°F for about 25 minutes, or until golden brown and cooked through.

Let the tarts cool down completely before un-moulding and garnisihng them.

Cut the zucchini and leek into matchsticks and sauté with the butter until soft.

Season with salt and pepper and keep aside.

Serve each tart warm, with a spoonful of sautéed vegetables and a slice of cotechino.