Rating: 3.5 stars
3 Ratings
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  • 1 star values: 1

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.

EatingWell.com, April 2022


Read the full recipe after the video.

Recipe Summary

25 mins
1 hr 5 mins


Ingredient Checklist


Instructions Checklist
  • 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.

  • 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.


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

1 slice
221 calories; protein 15g; carbohydrates 5g; dietary fiber 1g; sugars 1g; fat 16g; saturated fat 7g; mono fat 6g; poly fat 2g; cholesterol 248mg; vitamin a iu 1467IU; vitamin b3 niacin 2mg; vitamin b12 1mcg; vitamin c 5mg; vitamin d iu 55IU; vitamin e iu 2IU; folate 41mg; vitamin k 69mg; sodium 455mg; calcium 244mg; iron 2mg; magnesium 28mg; phosphorus 275mg; potassium 309mg; zinc 2mg; omega 6 fatty acid 2g; niacin equivalents 5mg; selenium 33mcg.