Cut the leaves off 2 medium or 1 large leek, then the shank in half lengthwise and wash well. Thinly slice the leek shank.
Heat 1 T. butter or olive oil in a heavy-bottomed skillet and add the leeks. Cook until wilted. Transfer to a bowl.
Rinse 1 bunch of asparagus, then trim or snap the tough bottoms. Slice on the diagonal in 1 inch pieces.
Rinse 2 stems of green garlic well, then cut just like the asparagus.
Chop 4 oz. fresh wild mushrooms (or re-hydrated dry wild mushrooms).
Saute the asparagus, garlic and mushrooms in 1 T. melted butter or olive oil with 2 t. fresh thyme leaves, for about 4 minutes. Season with salt and pepper.
Add the vegetables to bowl with the leeks.
Pour 3 1/2 C. mushroom broth into the saute pan along with , then mix in
1 1/2 C. heavy cream and 1 bay leaf. Simmer for 6 minutes, then whisk in 2 T. flour. Remove the bay leaf and add a dash of nutmeg.
Brush an 8 Cup baking dish with olive oil or butter. Make a layer of 1/2 C. sauce on the bottom. Add a single layer of lasagne noodles. Then a layer of vegetables, and finally a layer of 1/2 C. finely grated parmesan cheese. Repeat twice more. Top the lasagne with the remaining sauce and cover tightly with foil.
Bake for 40 minutes at 350 degrees, then uncover and bake another 6-8 minutes, until the top is browned and bubbling.