Baked Egg and Cheese Frittata with Spinach and Mushrooms

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · ·

A protein-rich breakfast casserole with tender spinach and mushrooms baked into a golden, cheese-stuffed center, perfect for starting your day keto-compliant. This american-inspired keto (low-carb) ready in about 33 minutes pairs large eggs, packed fresh spinach, sliced mushrooms for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 285 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 15 min Cook: 18 min Serves 4 American cuisine 285 cal/serving
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Ingredients

Instructions

  1. Step 1: Preheat oven to 375°F (190°C). Whisk 6 large eggs with 1/4 tsp salt and 1/8 tsp black pepper in a medium bowl until fully combined.
  2. Step 2: Melt 1 tbsp unsalted butter in an oven-safe skillet over medium heat. Add 1 minced garlic clove and cook for 30 seconds until fragrant, then stir in 1/2 cup sliced mushrooms and cook for 3 minutes until softened.
  3. Step 3: Add 1 cup packed fresh spinach to the skillet and cook for 1 minute until wilted. Pour the egg mixture over the vegetables, then sprinkle 1/2 cup shredded cheddar cheese evenly on top.
  4. Step 4: Transfer skillet to oven and bake for 15-18 minutes until edges are golden and center is set when gently shaken.

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Frequently asked questions

How long does Baked Egg and Cheese Frittata with Spinach and Mushrooms take to make?

Total time is about 33 minutes (15 min prep + 18 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Baked Egg and Cheese Frittata with Spinach and Mushrooms?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep large eggs from drying out.

Can I substitute ingredients in Baked Egg and Cheese Frittata with Spinach and Mushrooms?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Baked Egg and Cheese Frittata with Spinach and Mushrooms for a different number of people?

The recipe is written for 4 servings. Multiply each ingredient by (your serving target / 4). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

Is Baked Egg and Cheese Frittata with Spinach and Mushrooms low-carb?

Yes — this recipe is tagged low-carb based on its ingredient list. Always cross-check labels for packaged ingredients (sauces, broths, condiments) since formulations vary by brand.

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