Ingredients

• 1 bunch leeks, white and pale green parts only
  
• 1 clove garlic, finely chopped
  
• 3 tablespoons unsalted butter (for the leek stew)
  
• 1 cup heavy cream
  
• ¹/₂ lemon, juice only
  
• salt
  
• white pepper, freshly ground
  
• 1 pound mushrooms, mixed varieties such as portobella, shiitake, and whatever else you can find at the market
  
• 8 tablespoons unsalted butter (divided, for the mushrooms and the béchamel), plus more, as needed
  
• 6 tablespoons all-purpose flour
  
• 4 cups light cream or half-and-half
  
• 1 cup Parmesan cheese, freshly grated
  
• ¹/₂ teaspoon nutmeg, freshly grated
  
• 3 large eggs, lightly beaten
  
• 1 pound mozzarella cheese, grated or sliced
  
• 2 boxes no-boil lasagna noodles (or use regular lasagna noodles, pre-cooked in a pot of boiling salted water)