Spinach-Mushroom Baked Eggs
Add Preferred SourceHave you ever had an egg-in-a-hole? These Spinach-Mushroom Baked Eggs kind of like the grownup version. They’re warm, savory, and layered with toasted bread, creamy Gruyère, tender mushrooms, and perfectly baked eggs. It’s the kind of dish that feels cozy and rustic but still elegant enough for brunch. Once you’ve had these baked eggs, you’ll never want breakfast any other way!
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I enjoy this recipe for weekend breakfasts because it serves many with minimal effort. You build everything right in the baking dish, pop it in the oven, and let it bake into a comforting, cheesy brunch casserole. It’s also great for meal prep; you can assemble it the night before and bake it fresh in the morning. Whether you’re hosting brunch or treating yourself to a cozy breakfast, these baked eggs always deliver.
Ingredients
- Extra-virgin olive oil – You can also use nonstick cooking spray or go for max flavor with melted butter.
- Onion – I like the flavor of sweet onion, but you could also use red onion, shallots, or even cooking onions.
- White mushrooms – Or, jazz up this recipe with your favorite wild mushrooms.
- Kosher salt and freshly ground black pepper
- Baby spinach – Use fresh, not frozen spinach.
- Crusty white bread – I like using a heartier bread for this recipe so that the bread doesn’t dissolve. I love it with rye or any thick cut crusty bakery bread.
- Eggs – Extra large eggs will also work.
- Whole milk – You could also use heavy whipping cream.
- Shredded Gruyère cheese – Parmesan would be a good substitute, or if you like salty feta, use that but it won’t be quite so melty.
How to Make Spinach-Mushroom Baked Eggs
Scroll down for the full recipe card with exact measurements and printable instructions.
Start by preheating your oven to 350°F. Lightly brush a 9×13-inch ceramic baking dish with olive oil; I like using a silicone pastry brush for an even, no-mess coating.
Heat 2 tablespoons of olive oil in a large skillet over medium-high heat. Add the chopped onion and cook for about 8 minutes, stirring occasionally, until golden and softened.
Add the sliced mushrooms in a single layer and let them cook undisturbed for 2 minutes so they brown nicely and all the water has started to evaporate. Stir and cook another 3–4 minutes until tender. Season with ½ teaspoon salt and a few grinds of black pepper.
Add the baby spinach to the skillet and cook for 1–2 minutes until wilted. Remove from heat and let the mixture cool slightly.
Arrange the toasted bread slices in a single layer in your prepared baking dish, letting them overlap slightly. Spoon the mushroom-spinach mixture evenly over the bread. If prepping ahead, you can prepare it up to this point and then cover and refrigerate overnight.
Crack one egg onto each slice of bread. Season again with a bit of salt and pepper for flavor. Pour the milk evenly over the eggs and vegetables. Sprinkle the shredded Gruyère cheese over the top.
Bake for 25–30 minutes, or until the egg whites are fully set but the yolks still jiggle slightly in the center. A probe-style oven thermometer can help you avoid overbaking.
Let it stand for 5 minutes before serving.
Chef Jenn’s Tips
- Don’t skip browning the mushrooms; this adds tons of savory flavor.
- If you prefer firmer yolks, add 3–5 extra minutes of bake time.
- Sandwich bread isn’t a great choice for this recipe. Use fresh, thick-crust bakery bread or even rye bread so the bread holds up better under the milk and eggs.
Serving Suggestions
Serve Spinach-Mushroom Baked Eggs with breakfast potatoes, a tasty muffin, sliced tomatoes, or a simple salad for a complete brunch plate. It’s also wonderful with fresh fruit, crispy bacon, or a warm pot of coffee. The flavors are rich but balanced, so it pairs beautifully with both savory and light breakfast sides.
Storage
Store leftovers in an airtight container in the refrigerator for up to 2 days. Reheat gently in a 300°F oven until warmed through, or microwave in short 20-second bursts. The eggs may firm up slightly when reheated, but the flavors remain delicious. Freezing is not recommended, as the eggs and bread don’t thaw well.
Spinach-Mushroom Baked Eggs
Equipment
Ingredients
- 2 tablespoons extra-virgin olive oil plus more for brushing
- 1 small onion chopped
- 1/2 pound white mushrooms sliced
- Kosher salt
- black pepper freshly ground
- 6 cups baby spinach about 6 ounces
- 6 slices crusty white bread lightly toasted
- 6 large eggs
- 1/2 cup whole milk
- 3/4 cup Gruyère cheese shredded
Instructions
- Preheat the oven to 350°F. Lightly brush a 9-by-13-inch baking dish with olive oil.
- Heat 2 tablespoons of olive oil in a large skillet over medium-high heat.
- Cook the onion, stirring occasionally, until golden, about 8 minutes.
- Add the mushrooms and cook without stirring for 2 minutes, then stir and continue cooking until softened, about 4 minutes.
- Season with 1/2 teaspoon salt and pepper to taste.
- Stir in the spinach and cook until wilted, about 2 minutes. Remove from the heat and let cool slightly.
- Arrange the toasted bread slices in a single layer in the prepared baking dish, letting the edges overlap slightly.
- Spoon the mushroom-spinach mixture evenly over the bread. (If making ahead, cover and refrigerate overnight.)
- Crack one egg onto each slice of bread. Season lightly with salt and pepper.
- Pour the milk evenly over the top and sprinkle with the Gruyère cheese.
- Bake for 25 to 30 minutes, until the egg whites are set but the yolks are still slightly runny.
Notes
Chef Jenn’s Tips
- Don’t skip browning the mushrooms; this adds tons of savory flavor.
- If you prefer firmer yolks, add 3–5 extra minutes of bake time.
- Sandwich bread isn’t a great choice for this recipe. Use fresh, thick-crust bakery bread or even rye bread so the bread holds up better under the milk and eggs.
Nutrition
A Note on Nutritional Information
Nutritional information for this recipe is provided as a courtesy and is calculated based on available online ingredient information. It is only an approximate value. The accuracy of the nutritional information for any recipe on this site cannot be guaranteed.
