1. Grease a rectangular tart tin with a loose bottom* (36x14cm) lightly. Roll out the dough (if necessary) slightly larger than the tart tin and press the dough to the bottom and sides to create a nice quiche base. Cut off excess dough and set it aside.

2. Bring water with some salt to a boil in a small pot. Add the asparagus (cut off the dry ends first) and let it cook for about 3-4 minutes. Remove the asparagus from the pot, rinse it with cold water, and let it cool down.

3. Wash and dry the spring onions and cut them into rings. Wash the wild garlic and cut it into thin strips. Heat up a small frying pan or pot, add some olive oil, and add the onions and wild garlic. Cook for some time until soft and glossy. Remove from the heat and let cool down.

4. Preheat the oven to 190°C (375˚F). For the filling, mix eggs, sour cream, heavy cream, diced mozzarella, and half of the Gruyère cheese in a bowl until well combined. Season with salt and pepper. Go easy on the salt, though, since the smoked salmon is already often a bit salty.

5. Place the salmon in one layer on the bottom of the tart tin, sprinkle the onion mixture on top, and pour the filling into the form to cover everything. Place the pre-cooked green asparagus on top and sprinkle everything with the remaining cheese. Bake the quiche for about 30-35 minutes until golden brown on top. If the quiche gets too dark, cover it with some aluminum foil and continue baking. Take it out of the oven and let it cool down for some time. Serve warm with some salad, for example.