Spinach, Mushroom & Egg Casserole


This delightful spinach, mushroom and egg casserole is layered with earthy cooked mushrooms and baby spinach, fluffy eggs and nutty cave-aged Gruyère that deepens the flavor. Serve this easy casserole for breakfast, brunch or even dinner with a green salad on the side.

Active Time:
25 mins
Total Time:
1 hr 5 mins


  • 2 tablespoons extra-virgin olive oil

  • 1 pound cremini mushrooms, trimmed and sliced

  • 5 medium cloves garlic, finely chopped

  • 2 teaspoons dry mustard

  • 1 teaspoon onion powder

  • 1 teaspoon salt

  • 5 ounces baby spinach

  • 12 large eggs

  • ¾ cup half-and-half

  • 1 ½ cups shredded Gruyère cheese, preferably cave-aged (see Tip), divided

  • 2 teaspoons fresh thyme leaves


  1. Preheat oven to 375°F. Coat a 9-by-13-inch baking dish with cooking spray. Heat oil in a large skillet over medium-high heat. Add mushrooms in an even layer; cook, undisturbed, until starting to brown, 5 to 6 minutes. Stir and continue to cook, undisturbed, until golden brown on the bottom, about 3 minutes. Stir and continue to cook, stirring occasionally, until the mushrooms are browned all over and the liquid has evaporated, about 3 minutes. Add garlic, dry mustard, onion powder and salt; cook, stirring constantly, until fragrant, about 1 minute. Add spinach and cook, stirring constantly, until the spinach wilts, 1 to 2 minutes. Set aside to cool slightly, about 10 minutes.

  2. Crack eggs into a large bowl and whisk until completely smooth. Add half-and-half and whisk until combined. Reserve 1/2 cup of the vegetable mixture; scatter the remaining mixture in the prepared baking dish. Sprinkle evenly with 3/4 cup Gruyère. Pour the egg mixture over the top. Sprinkle evenly with the remaining 3/4 cup Gruyère and the reserved 1/2 cup vegetable mixture. Bake until puffed, golden brown and just set, 30 to 35 minutes. Let cool slightly, about 10 minutes. Sprinkle with thyme before serving.

    Spinach, Mushroom & Egg Casserole
    Greg Dupree


Cave-aged Gruyère is aged for at least a year in caves that provide the perfect environment for aging which intensifies the flavor and hardens the texture of the cheese. Look for it in well-stocked supermarkets, specialty cheese shops or online. While cave-aged Gruyère adds depth of flavor to this recipe, regular Gruyère will work well too.

Nutrition Facts (per serving)

221 Calories
16g Fat
5g Carbs
15g Protein
Nutrition Facts
Servings Per Recipe 10
Serving Size 1 slice
Calories 221
% Daily Value *
Total Carbohydrate 5g 2%
Dietary Fiber 1g 4%
Total Sugars 1g
Protein 15g 30%
Total Fat 16g 21%
Saturated Fat 7g 35%
Cholesterol 248mg 83%
Vitamin A 1467IU 29%
Vitamin C 5mg 6%
Vitamin D 55IU 14%
Vitamin E 1mg 9%
Folate 41mcg 10%
Vitamin K 69mcg 58%
Sodium 455mg 20%
Calcium 244mg 19%
Iron 2mg 11%
Magnesium 28mg 7%
Potassium 309mg 7%
Zinc 2mg 18%
Vitamin B12 1mcg 42%

Nutrition information is calculated by a registered dietitian using an ingredient database but should be considered an estimate.

* Daily Values (DVs) are the recommended amounts of nutrients to consume each day. Percent Daily Value (%DV) found on nutrition labels tells you how much a serving of a particular food or recipe contributes to each of those total recommended amounts. Per the Food and Drug Administration (FDA), the daily value is based on a standard 2,000 calorie diet. Depending on your calorie needs or if you have a health condition, you may need more or less of particular nutrients. (For example, it’s recommended that people following a heart-healthy diet eat less sodium on a daily basis compared to those following a standard diet.)

(-) Information is not currently available for this nutrient. If you are following a special diet for medical reasons, be sure to consult with your primary care provider or a registered dietitian to better understand your personal nutrition needs.

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