We layer a lasagna the same way we top a pizza–with a light hand. Forget about over-stuffed layers and an overflowing casserole dish. You want to scatter just enough cheese and vegetables on the layers to flavor, but not overwhelm. If you use fresh pasta that's rolled very thin, you can even form eight or ten layers. With dried or thicker pasta sheets, you'll want fewer layers.

This delicate vegetarian lasagna plays up the cheese, complementing it with the flavors of mushrooms and spinach. Try experimenting with different types of mushrooms, but salt them sparingly as the Parmesan acts as salt in this dish.

You can use any fresh mushrooms you like. We use a combination of two-thirds crimini and one-third shiitake mushrooms for a good flavor without too much expense.

Don't worry about the size of your pan. Just make sure the pans you choose are deep enough to hold at least five layers. - Sue Conley & Peggy Smith (Co-Founders)

Serves 8 to 10

Ingredients

2 tbsp Dried porcini mushrooms
3 cups Milk (whole or low-fat)
3 tbsp plus 1 tsp Unsalted butter
4 cups Fresh spinach leaves
½ tsp Sea salt
½ tsp Freshly ground black pepper
1 tbsp Extra-virgin olive oil
1½ cups Chopped yellow onion
4 Garlic cloves, chopped
6 cups Sliced fresh mushrooms
2 tbsp All-purpose flour
1 lb Fresh pasta sheets or dried lasagna noodles
8 oz Gruyère or Wagon Wheel, grated
6 oz Fromage Blanc
1 oz Parmesan cheese, grated

Directions

1. Wrap the dried porcinis in cheesecloth tied with string. Heat the milk in a medium saucepan over medium-high heat until small bubbles form. Take off the heat and place the porcini in the milk. Let it steep for 1 hour at room temperature.
2. Meanwhile, melt the 1 tsp butter in a large skillet over medium-high heat. Add the spinach, salt, and a few grinds of black pepper and decrease the heat to medium.Cook,tossing now and then,until the spinach has shrunk by half but is   still green, about 3 minutes. Transfer the spinach to a bowl to cool. Wipe out the pan.
3. Heat the olive oil and 1 tbsp butter in the skillet over medium heat. When the butter is melted, add the onion and garlic to the pan. Sauté, stirring just until the onion softens; add the fresh mushrooms. Cook until the mushrooms begin to show some brown, about 10 minutes over medium heat. Take the pan off the heat and set it aside.
4. After 1 hour, squeeze as much milk as you can out of the porcinis into a bowl. Empty the mushrooms into another bowl and discard the cheesecloth.
5. Using the porcini-steeped milk, the remaining 2 tbsp butter, and the flour, make a béchamel.  
6. Preheat the oven to 400°F. Bring a large pot of water to a boil over medium-high heat for the pasta. Butter a lasagna pan or deep baking dish.
7. Cook the pasta and divide the mushrooms into three equal portions and the spinach into two equal portions, and have all the cheeses and béchamel ready for layering.
8. For the bottom layer, arrange the pasta starting at the pan's center and let the bottom half of each pasta sheet drape over the pan's sides. Sprinkle one-third of the mushrooms over the bottom pasta layer. Sprinkle lightly with one-third of the Gruyère or Wagon Wheel. Add another pasta layer. Add béchamel sauce, smoothing it over the pasta. Arrange half the spinach on the pasta and top with half the Fromage Blanc, dropping small spoonfuls on top of the spinach. Add another neat layer of pasta. Repeat with another mushroom and Gruyère layer, more pasta, and another béchamel, spinach, and fromage blanc layer. After the finnal mushroom layer, fold over the pasta edges that have hung over the pan sides all this time. Give the top a final light layer of béchamel, smoothing it evenly over the pasta, sprinkle with Parmesan, and cover the top with aluminum foil.
9. Bake for 20 minutes, then remove the foil and decrease the oven temperature to 350°F. Cook until the cheese on top is bubbly and starting to brown, another 15 to 20 minutes. Take the lasagna out of the oven and let it cool for at least 15 minutes before serving.