Peel the asparagus and cut off the woody ends. Cut asparagus diagonally into bite-sized pieces. Peel and wash the carrots, cut them in half lengthwise and cut them diagonally into pieces. Wash sugar snap peas, dab dry, halve or cut into three. Peel and chop the onion
Heat the oil in a pan. Fry the asparagus, carrots and onion for 3-4 minutes, turning them over. Add the pods and steam for another 2-3 minutes, season with salt and pepper, place the vegetables in a bowl and allow to cool
Take the puff pastry out of the refrigerator 5-10 minutes before use. In the meantime, peel garlic and chop finely. Mix with sour cream and eggs, season with salt, pepper and sugar. Unroll the dough on the baking paper, place it in a rectangular tart or baking tin (top: 21 x 29 cm; bottom: 19.5 x 27.5 cm) with the baking paper facing down. Pour in the vegetable mixture and pour over the mixture with a sand glaze. Grate the gouda, pluck the mozzarella. Spread both on the tart
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for 30-35 minutes until the egg mass has set. Finally, cover with foil if necessary. Remove the tart, let it cool down a little, garnish with chervil if necessary. Serve with herbal sour cream