Spinach Mushroom Lasagna

Name: Spinach Mushroom Lasagna
Prep time: 50 min
Cook time: 38 min
Total time: 1 h 28 min
Yield: 12 servings
Ingredients: 1 10 oz package frozen spinach thawed and squeezed dry; 12 lasagna noodles; 3 tbsp unsalted butter divided; 1 medium onion finely chopped; 3 cloves garlic minced; 12 oz cremini mushrooms chopped; 1 tsp Italian seasoning; 1 tsp salt divided; 1/2 tsp black pepper divided; 1 15 oz container whole milk ricotta cheese; 3/4 cup grated Parmesan cheese divided; 2 cups shredded mozzarella cheese divided; 2 large eggs; 1/4 cup chopped fresh parsley; 4 cups whole milk; 3 tbsp all purpose flour; Pinch ground nutmeg; Olive oil for drizzling; Nonstick spray; Optional twist: swap cremini mushrooms with finely chopped eggplant for earthier tone

By Emma

Certified Culinary Professional

Published on 27 October 2025 • Recipe tested & approved

Layers of sautéed mushrooms and thawed spinach combined with a ricotta blend, nestled between sheets of tender lasagna noodles and a creamy white sauce enriched with Parmesan and nutmeg. Baked until bubbly and golden brown with mozzarella melting on top. A bit of parsley freshens the mix. Layers repeated thrice, assembled carefully, with noodles torn to fit. Cheesecloth or a trusty steamer basket saves watery spinach woes. The white sauce uses roux for thickness, milk slowly whisked in to avoid lumps. Foil trick keeps moisture during baking. Broil if you dare, but eyes on the prize — golden, bubbling, ready to slice and cool.

Prep: 50 min

Cook: 38 min

Total: 1h 28min

Servings: 12 servings

#Italian-American #vegetarian #lasagna #white sauce #ricotta #mushrooms #spinach

Before You Start

Spinach and mushrooms in a ricotta mix. Creamy white sauce with nutmeg whisper. Every time I made lasagna with just spinach and cheese it turned watery or bland—mushrooms add earth and chew. Squeezing spinach until nearly dry is a kitchen life-saver. Noodles are delicate, not overcooked or they crumble, so rinse cold right away. White sauce demands patience; rushed milk rush clumps and lumps. Using roux is old school but magic—thickens slowly, glosses over ingredients, warms the soul. Foil sprayed nonstick side, no stuck cheese mishaps. You’ll see bubbling margins through foil, smell toasted edges, that’s when you know. Slice after cooling or all goes slide-slush. Learned from years of burnt bottoms and wet middles—this works every time.

Ingredients

1 10 oz package frozen spinach thawed and squeezed dry
12 lasagna noodles
3 tbsp unsalted butter divided
1 medium onion finely chopped
3 cloves garlic minced
12 oz cremini mushrooms chopped
1 tsp Italian seasoning
1 tsp salt divided
1/2 tsp black pepper divided
1 15 oz container whole milk ricotta cheese
3/4 cup grated Parmesan cheese divided
2 cups shredded mozzarella cheese divided
2 large eggs
1/4 cup chopped fresh parsley
4 cups whole milk
3 tbsp all purpose flour
Pinch ground nutmeg
Olive oil for drizzling
Nonstick spray
Optional twist: swap cremini mushrooms with finely chopped eggplant for earthier tone

About the ingredients

Frozen spinach often comes waterlogged. Squeeze it out well with cheesecloth or metal basket press to avoid soggy layers. I swapped cremini mushrooms with finely diced eggplant once—added deeper earthy notes but took longer to cook down. Butter in sautéing adds richness; olive oil can substitute but changes flavor profile. Parmesan is crucial for sharpness, but pecorino Romano can replace for punchier tang. Eggs bind ricotta mix; don’t skip or fillings go loose. Flour for roux must be cooked briefly to avoid raw taste. Milk whole fat or 2% for creaminess; skim results in thinner sauce. If short on fresh parsley, dry herb is okay, but fresh is worth the chopping. Lasagna sheets—no boiling no-go is tempting, but I’ve found boiling then oiling prevents clumping and tearing while assembling. Fresh pasta can be substituted but watch cooking times.

Method

Defrost frozen spinach fully, then squeeze out as much water as possible. Don’t skip this part or risk watery layers. My hack: put thawed spinach in a metal steamer basket, clasp sides tight, twist and press firmly or use cheesecloth to wring it dry. Much better than soggy paper towels that fall apart and waste time.
Bring large pot salted water to vigorous boil—drop noodles in one by one making sure they don’t stick. Cook till just shy of firm bite; al dente means a little resistance inside. Drain into colander and rinse with cold water immediately to stop cooking. Spread them flat onto parchment sheets and drizzle sparingly with olive oil. Keeps sheets from clumping when layering later.
Heat 2 tablespoons butter in large nonstick skillet over medium high. Toss in onion with half salt, half pepper. Sauté 2-4 minutes until translucent and fragrant, edges just caramelizing. Add garlic, stir 1 more minute letting aroma pop. Throw in chopped mushrooms and Italian seasoning. Mushrooms will sweat liquid fast; stir occasionally till it evaporates, about 8-12 minutes, browning slightly for that umami kick. Off heat, add squeezed spinach, season to taste with remaining salt and pepper. Let cool enough to avoid scrambling eggs next.
In big bowl whisk ricotta with half Parmesan, half mozzarella, eggs, and parsley to bind with richness. Fold this into mushroom spinach mix once cooled fully. This combo gives texture and depth—don’t rush cooling or your eggs will cook early and clump.
White sauce next. Melt 1 tbsp butter in heavy saucepan over medium heat. Whisk in flour swiftly to create roux; bubbles only, no brown. Gradually, as if coaxing, drizzle milk in bursts whisking furiously between. This builds velvety sauce without lumps. Keep stirring over medium heat until sauce thickens and skirts the pan like a pudding, bubbles popping at edges. Off heat, stir in remaining Parmesan, pinch nutmeg (don’t skip—just a whisper), salt and pepper to taste.
Preheat oven to 375F. Grab 9x13 oven-proof dish. Spoon about 1/2 cup of white sauce swirling around the bottom—thin even layer keeps noodles from sticking.
Lay down first layer noodles, tearing if needed to cover gaps. Dollop 1/3 spinach ricotta mixture on top. Spread evenly but not too thin or it will dry out. Cover that with another 1/2 cup white sauce. Layer again noodles, spinach mix, sauce. Repeat a third time.
Final noodle layer goes on with remaining white sauce spread over and last handful mozzarella sprinkled generously. Cheese on top browns nicely in oven plus adds that bubbling crust everyone loves.
Spray one side of foil with nonstick spray—the greasy side faces down to prevent cheese sticking to foil instead of letting it cling to your layers. Cover dish tightly. Bake for 28-33 minutes covered (watch edges bubbling through foil), then uncover and bake another 12 minutes or till brown and bubbly. For impatient types, 1-2 minutes under broiler gives top a nice bronzed crunch but watch closely—you’ll smell burning fast.
Cool lasagna at least 15 minutes before slicing so layers set and gooey cheese doesn’t run off. Leftovers keep well wrapped in fridge for 3 days, reheat low and slow to keep sauce luscious.

Cooking tips

Spinach moisture is enemy of creamy filling—wring it dry, trust me. Sauté mushrooms till liquid evaporates completely or layers turn watery and flat. Let mixture cool before mixing with eggs; hot mixture scrambles eggs instantly ruining texture. When whisking roux and milk, add milk slowly in small increments, whisk constantly to prevent grainy lumps. Sauce thickens when it coats spoon back thickly with stir marks visible—this is your cue. Layer noodles carefully, tearing edges for perfect fit; gaps mean dry edges after baking. Spread white sauce evenly on each layer to maintain moisture balance. Covering lasagna with sprayed foil prevents cheese sticking to foil—classic rookie mistake to skip this. Bake covered first to steam heat through, crisping top only after foil removal. Broiling optional but watch under intense heat; smells burnt when too far gone. Cooling after baking lets cheese and sauce solidify slightly for neat slicing without collapse.

Chef's notes

💡 Spinach moisture kills texture. Squeeze hard or use cheesecloth. Metal basket press works too. Any leftover liquid makes layers soggy and collapse. Dry as you can before mixing in ricotta for body.
💡 Mushrooms sweat fast. Sauté without lid until all water evaporates, don’t rush this or filling gets watery. Brown spots signal umami kicking in. Off heat, add spinach once mushrooms cool down to prevent eggs scrambling.
💡 Whisk roux carefully. Flour must cook in melted butter but no brown. Drizzle milk in slow, small increments. Constant whisking or lumps form fast. Sauce thickens when it coats back of spoon, no raw flour taste allowed.
💡 Tear noodles to patch gaps for full, even coverage. No dry edges later. Oil noodles lightly after boiling to avoid sticking. Drain and rinse cold fast to stop cooking. Then layer carefully with fillings, white sauce evenly spread for moisture balance.
💡 Foil sprayed on one side, grease down to prevent cheese sticking. Cover tightly to steam layers first, then uncover for golden top browning. Broiling optional but watch closely. Burning smells quick if left too long.

Common questions

Why squeeze spinach no water?

Water adds sogginess. Layers flatten. Using metal basket or cheesecloth wrings moisture. Spinach soft and less dense otherwise. Must dry or filling gets runny.

Can mushrooms be swapped?

Eggplant works but cooks slower and absorbs more oil. Button mushrooms milder, less umami. Cremini ideal for flavor and texture. More liquid if not cooked down fully.

How to avoid clumpy white sauce?

Roux must cook briefly first. Milk added slowly, whisk fast. Stove heat medium steady. Sauce thickens when coating back of spoon thick with whisk marks. If lumps form, strain or blitz quickly.

Storing leftovers?

Wrapped tight, fridge good 3 days. Reheat low and slow to keep creamy sauce. Freezing okay but texture shifts. Thaw overnight, reheat gentle. Avoid microwave overheating or drying out layers.