White Truffle Mushroom Lasagna with Crispy Sage Tips, FAQ & printable recipe

Tips for success

Brown the mushrooms in two batches if the skillet looks crowded; a layer of mushrooms touching the pan browns, a pile of them steams.

Resist stirring for the first few minutes so each slice develops a bronze underside. Salt them only at the end — salting early draws out water before the browning happens.

Grate the Fontina on the large holes of a box grater so it melts in two or three additions rather than one heavy clump, which can break the emulsion.

Keep the sauce at a bare simmer once the cheese goes in, and whisk in one direction. If the kitchen is humid, the fried sage can soften; re-crisp it for 30 seconds in a dry pan just before serving.

Variations

• No-boil noodle version: Swap the fresh sheets for no-boil dried lasagna noodles and thin the béchamel with an extra half cup of milk. The dried pasta drinks up the sauce as it bakes, so the slightly looser béchamel keeps every layer tender and creamy.
• Dried porcini boost: Simmer 1/2 ounce of dried porcini in the milk for 10 minutes, then strain before making the béchamel. The milk turns deeply savory and the truffle notes read stronger, even without truffle-infused milk on hand.
• Spinach layer: Wilt 10 ounces of baby spinach, squeeze it dry, and scatter it over the mushrooms in each layer. The greens add color and a bitter edge that plays well against the sweet, nutty Fontina sauce.
• Individual ramekins: Assemble in six buttered ramekins with the same layering order and bake at 385°F for about 22 minutes. Each ramekin gives every diner a fully blistered top and caramelized edges — ideal for dinner parties.

Storage and make-ahead

Fridge

Cover tightly and refrigerate up to 4 days; the béchamel firms as it chills, making reheated slices even neater.

Freezer

Freeze baked or unbaked, wrapped well, up to 2 months. Thaw overnight in the refrigerator before reheating.

Reheat

Reheat covered at 325°F for 20 to 25 minutes, uncovering for the last 5 to re-crisp the top.

Cool leftovers at room temperature for no more than 2 hours, then cover the dish tightly or transfer squares to an airtight container. The lasagna keeps in the refrigerator for up to 4 days; the béchamel firms as it chills, which actually makes for neater reheated slices.

Assemble the full lasagna up to 24 hours ahead: layer everything, cover the dish, and refrigerate without baking. Add 5 to 10 minutes to the bake time since it starts cold.

The béchamel and sautéed mushrooms can also be made a day ahead and refrigerated separately; rewarm the sauce gently before layering so it spreads evenly.

Serving ideas

Serve the lasagna hot from the dish, cut into eight squares with a wiped blade for clean edges. A wide spatula keeps the creamy layers stacked as each slice travels to the plate. The corner pieces deliver the most blistered, chewy edges, so distribute them deliberately.

This is rich enough to anchor the whole meal with just a sharp, lemony salad alongside — arugula or endive cuts through the béchamel beautifully.

A final pass of the microplane over each plate, whether with truffle or Parmesan, and one extra crispy sage leaf per slice finishes it.

Frequently asked questions

Recipe card

White Truffle Mushroom Lasagna with Crispy Sage

Prep 35 minCook 45 minRest 10 minTotal 1 h 30 minServes 8

Ingredients

• 4 tbsp unsalted butter, divided
• 1 1/2 lb mixed mushrooms (porcini and cremini), sliced
• 3 cloves garlic, minced
• 12 fresh sage leaves, plus extra for serving
• 1/3 cup all-purpose flour
• 3 cups whole milk, truffle-infused if available, warmed
• 7 oz Fontina cheese, shredded
• 1 lb fresh lasagna sheets
• black truffle, shaved, for serving (optional)

Instructions

1. Melt 1 tablespoon of the butter in a large skillet over medium heat until it foams. Lay the sage leaves in a single layer and fry for 20 to 30 seconds per side, just until they turn deep green and crisp at the edges. Lift them onto a paper towel and salt lightly.
2. Add another tablespoon of butter to the same skillet and raise the heat to medium-high. Add the sliced mushrooms in an even layer and cook, stirring rarely at first, for 8 to 10 minutes, until they release their liquid and it evaporates. Stir in the garlic during the last minute, then season and scrape into a bowl.
3. Melt the remaining 2 tablespoons of butter in a medium saucepan over medium heat. Whisk in the flour and cook for 2 minutes, stirring constantly, until the paste smells faintly nutty and turns the color of pale sand. Do not let it take on color — a dark roux will dull the white sauce.
4. Pour in the warm truffle-infused milk a splash at a time, whisking until completely smooth before adding more. Once all the milk is in, bring the sauce to a gentle simmer and cook for 4 to 5 minutes, until it thickens enough to coat the back of a spoon. Season with salt, pepper, and nutmeg.
5. Lower the heat to its minimum and add the shredded Fontina a handful at a time, whisking until each addition melts before the next goes in. Keep the sauce barely simmering — never boiling — until it looks glossy and velvety. Taste and adjust the salt, then set aside off the heat.
6. Heat the oven to 385°F (195°C). Spread a thin veil of béchamel over the bottom of a 9x13-inch baking dish. Layer fresh pasta sheets, a third of the mushrooms, and a generous ladle of béchamel, repeating three times and finishing with sauce on top. Reserve a few spoonfuls of mushrooms for garnish.
7. Bake on the middle rack for 30 minutes, until the top blisters into golden-brown peaks and the sauce bubbles at the edges of the dish. If the surface colors too quickly, lay a sheet of foil loosely over the pan for the final 10 minutes. The corners should look deeply caramelized.
8. Transfer the dish to a wire rack and let it rest for 10 minutes. The bubbling slows and the layers set enough to cut clean corners instead of sliding apart. Do not skip this — a lasagna cut straight from the oven pours rather than slices.
9. Scatter the reserved sautéed mushrooms over the top, then shave black truffle generously across the surface with a microplane or truffle shaver. Crown each future slice with a couple of the crispy sage leaves so they stay intact and shatter when served.
10. Cut the lasagna into 8 squares with a sharp knife, wiping the blade between cuts for clean edges. Lift each slice with a wide spatula so the creamy layers stay stacked. Serve hot, while the béchamel still moves slowly and the sage crackles on top.

Contains: gluten, milk

Estimated nutrition per serving

Calories

640

Protein

24 g

Carbohydrates

48 g

Fat

38 g

Automatic estimate from the ingredient list, not laboratory-verified.