1. Peel the asparagus if necessary and cut them into 2-3 cm pieces. Blanch them for 2 minutes, along with the peas and sugar snap peas, in a pot of salted boiling water. Remove them with a slotted spoon and immediately plunge them into a bowl of ice water. Drain them.
2. Chop the chives and garlic. Mix them with the vegetables in the bowl.
3. Slice the onion and sauté it for 2-3 minutes in a pot, in butter. Add the flour and cook for 2-3 minutes over medium heat, stirring constantly. Add a little broth and mix. Season with salt and pepper. Gradually pour in the remaining broth and let it thicken over medium heat, stirring. Once you have a creamy sauce, remove the pot from the heat, add the fresh cheese and nutmeg. Mix well and adjust the seasoning if necessary.
4. Preheat the oven to 180°C. Spread sauce on the bottom of a baking dish. Arrange 3-4 lasagna sheets and cover with a layer of vegetables. Spread sauce over it and repeat the process until all the ingredients are used. Finish with a layer of sauce and sprinkle with parmesan. Bake for about 40 minutes, until the lasagna is golden brown and bubbly.