Spinach, Mushroom, and Potato Casserole with Béchamel Sauce

This comforting Spinach, Mushroom & Potato Casserole layers silky mashed potatoes, sautéed mushrooms and spinach, and a luscious homemade béchamel sauce, all crowned with melted cheese. Inspired by classic gratins and shepherd’s pies, it transforms humble ingredients into a show-stopping dish perfect for weeknight dinners, potlucks, or cozy family gatherings. Each forkful offers fluffy potato, tender vegetables, and creamy sauce—an irresistible blend of textures and flavors that will become a new favorite in your recipe repertoire.

Cooking Time

• Preparation: 25 minutes

• Potato boiling: 10–12 minutes

• Vegetable sauté: 10 minutes

• Béchamel preparation: 8 minutes

• Assembly & Baking: 30 minutes

• Resting: 15 minutes

• Total Active Time: 53 minutes

• Total Passive Time: 57 minutes

Ingredients

Potato Purée Layer

• 5 large potatoes (≈1.2 kg), peeled and cut into 3 cm cubes

• 2–3 Tbsp unsalted butter

• 1 cup (250 ml) whole milk, warmed

• Salt, to taste

Spinach & Mushroom Layer

• 1 large onion, diced

• 4 Tbsp olive oil, divided

• 500 g fresh spinach, washed and roughly chopped

• 300 g mushrooms (button or cremini), sliced

• Salt, freshly ground black pepper, and red pepper flakes, to taste

Béchamel Sauce

• 3 Tbsp olive oil or 2 Tbsp unsalted butter

• 2 Tbsp all-purpose flour

• 1½ cups (375 ml) milk, warmed

• Pinch of freshly grated nutmeg

• Salt, to taste

Assembly & Topping

• 100–150 g freshly grated kaşar or mozzarella cheese

Step-by-Step Cooking Directions

1. Cook Potatoes: Place diced potatoes in a large pot, cover with cold water, add a pinch of salt, and bring to a boil. Simmer 10–12 minutes until easily pierced with a fork. Drain well and return to the pot.

2. Make Potato Purée: Mash the hot potatoes, adding 2 Tbsp butter and warm milk a little at a time until you reach a smooth, creamy consistency. Season with salt to taste. Set aside.

3. Sauté Onions & Mushrooms: In a wide skillet over medium heat, warm 2 Tbsp olive oil. Add diced onion and sauté 3–4 minutes until translucent. Add sliced mushrooms, season lightly with salt and pepper, and cook another 5 minutes until moisture evaporates.

4. Add Spinach: Push mushrooms to one side, add remaining oil, then stir in chopped spinach. Season with salt, pepper, and red pepper flakes. Cook 2–3 minutes until spinach wilts. Remove from heat.

5. Prepare Béchamel: In a saucepan, heat olive oil or butter over medium heat. Whisk in flour and cook 1 minute to form a roux. Gradually whisk in milk until smooth. Simmer, whisking constantly, until thickened (2–3 minutes). Stir in nutmeg and salt. Remove from heat.

6. Combine Vegetables & Sauce: Pour béchamel into the spinach–mushroom mixture, stirring until fully incorporated. Taste and adjust seasoning.

7. Assemble Casserole: Preheat oven to 180 °C (350 °F). Spread mashed potatoes evenly in an ovenproof dish. Top with the spinach–mushroom–béchamel mixture, smoothing to the edges.

8. Add Cheese & Bake: Sprinkle grated cheese evenly over the top. Bake 30 minutes or until cheese is bubbling and golden. Turn off oven and let rest 15 minutes before serving.

Nutritional Information

(Per serving; serves 6)

• Calories: 350 kcal

• Protein: 12 g

• Total Fat: 18 g

  • Saturated Fat: 8 g

• Carbohydrates: 36 g

  • Fiber: 4 g

  • Sugars: 6 g

• Sodium: 420 mg

• Calcium: 15% DV

• Iron: 12% DV

The Origins and Popularity of the Recipe

This casserole combines elements of French gratin (béchamel and cheese) with British-style mashed-potato layering and Mediterranean sautéed vegetables. Variations of vegetable–potato bakes appear across Europe and the Middle East, prized for their economical ingredients and hearty status. The added béchamel elevates it from peasant fare to a refined bake, while spinach and mushrooms bring vibrant color and nutrients to a classic comfort-dish template.

Reasons Why You’ll Love This Recipe

• One-Dish Meal: Layers of protein, starch, and vegetables all in one pan.

• Make-Ahead Ease: Prep components ahead for quick assembly.

• Customizable: Swap in kale, leeks, or roasted peppers to suit preferences.

• Vegetarian-Friendly: No meat, yet deeply satisfying and protein-rich from dairy.

• Crowd-Pleaser: Familiar flavors with a gourmet twist, perfect for guests.

Health Benefits

• Vitamin-Rich Spinach: Provides vitamins A, C, and K plus folate.

• Mushroom Antioxidants: Selenium and ergothioneine support immune health.

• Calcium from Dairy: Beef up bone-strengthening calcium via milk, butter, and cheese.

• High Fiber: Potatoes and spinach aid digestion and satiety.

• Controlled Fats: Uses moderate amounts of healthy olive oil and milk fat.

Serving Suggestions

• Light Lunch: Pair with a crisp arugula salad dressed in lemon vinaigrette.

• Hearty Dinner: Serve alongside grilled chicken or seared fish for extra protein.

• Vegetarian Spread: Include with roasted vegetable platters and crusty bread.

• Brunch: Accompany with poached eggs and fresh tomato slices.

Common Mistakes to Avoid

• Watery Vegetables: Sauté mushrooms until moisture evaporates to avoid a soggy bake.

• Lumpy Béchamel: Whisk constantly when adding milk to the roux for a silky sauce.

• Underseasoned Layers: Season each component—potatoes, vegetables, and sauce—for balanced flavor.

• Skipping Rest Time: Let the finished casserole rest so layers set and are easier to serve.

• Overdry Mash: Retain some moisture in the potatoes for a creamy first layer.

Pairing Recommendations

• Wine: A crisp Chardonnay or a light Pinot Noir complements the creamy texture and earthy mushrooms.

• Beer: A Belgian witbier or pilsner refreshes the palate between rich bites.

• Non-Alcoholic: Sparkling water with a twist of lemon or a herbal mint tea balances the bake’s richness.

Cooking Tips

• Uniform Potato Cubes: Cut potatoes into equal sizes for even boiling.

• Warm Dairy: Heat milk slightly before adding to béchamel to prevent lumps.

• Cheese Variations: Substitute Gruyère, Fontina, or kefalotyri for regional flair.

• Layer Thickness: Keep potato and vegetable layers roughly equal for balanced texture.

• Make It Lighter: Use low-fat milk and reduce butter by 1 Tbsp for a lighter version.

Similar Recipes to Try

• Shepherd’s Pie: Seasoned ground lamb or beef under mashed potatoes.

• Vegetable Moussaka: Layers of eggplant, potato, and béchamel in Greek style.

• Broccoli & Cheese Au Gratin: Broccoli florets baked in cheese sauce with breadcrumbs.

Variations to Try

• Leek & Bacon Upgrade: Sauté leeks and bacon in place of mushrooms for smoky flavor.

• Mediterranean Twist: Add roasted red peppers, olives, and feta cheese.

• Vegan Adaptation: Swap béchamel for cashew cream and use vegan cheese.

• Spicy Kick: Stir in red pepper flakes or chopped jalapeño to the vegetable layer.

Ingredient Spotlight

Béchamel Sauce: The French “mother sauce” of butter, flour, and milk forms a silky binder that coats each vegetable piece, preventing dryness and lending a luxurious mouthfeel. A dash of nutmeg adds subtle warmth and depth.

Conclusion

This Spinach, Mushroom & Potato Casserole with Creamy Béchamel unites simple ingredients into a memorable, layered bake. Its tender potato base, savory vegetable filling, and luscious cheese topping make it a versatile dish for any meal. With straightforward steps, customizable variations, and make-ahead convenience, it’s destined to become a weeknight staple or celebratory favorite. Gather your ingredients, preheat the oven, and enjoy the rich comfort of this delightful casserole.

Frequently Asked Questions

1. Can I use frozen spinach?
   Yes—thaw and drain thoroughly before sautéing to avoid excess moisture.

2. How do I prevent a skin from forming on béchamel?
   Press plastic wrap directly onto the sauce surface while it cools.

3. Is a casserole dish required?
   Any ovenproof baking dish (glass or ceramic) will work; adjust cooking time slightly if shallow.

4. Can I make it ahead?
   Assemble up to 24 hours in advance, refrigerate, then bake fresh before serving.

5. What if I don’t have kaşar cheese?
   Mozzarella, Gruyère, or cheddar all melt beautifully as gratin toppings.

6. How do I reheat leftovers?
   Cover with foil and warm at 175 °C (350 °F) for 10–12 minutes in the oven.

7. Can I add protein?
   Layer cooked chicken breast or crumbled sausage between the potato and vegetable layers.

8. Why add nutmeg to the sauce?
   Nutmeg enhances the creamy sauce with a hint of earthy warmth, balancing the dairy’s sweetness.

9. How can I make it gluten-free?
   Use a gluten-free all-purpose flour blend in the béchamel and ensure any flour substitutes are certified GF.

10. What other vegetables work?
    Try Swiss chard, kale, zucchini, or roasted peppers for seasonal variation.