Overnight Breakfast Strata with Caramelized Onions and Mushrooms
A make-ahead breakfast casserole that transforms day-old bread into a custardy, savory masterpiece. Caramelized onions bring sweetness while earthy mushrooms and fresh thyme add depth. Layers of sourdough soak up a rich egg custard studded with creamy goat cheese and sharp gruyere. Perfect for holiday mornings, brunch gatherings, or feeding a crowd without morning stress. The overnight rest allows flavors to meld and creates the signature puffed, golden top that makes strata irresistible.
Ingredients
- 1 loaf crusty sourdough or french bread, about 8 cups cubed
- 4 slices bacon(optional)
- 1 tablespoon oil
- 1 onion, very thinly sliced into rings
- 1 tablespoons butter
- 1 pound mushrooms, sliced
- 3 tablespoons fresh thyme leaves
- 10 large eggs
- 1 ½ cups whole milk, or half and half
- 1 cup sour cream
- 1 teaspoon salt
- ½ teaspoon pepper
- 4 ounces goat cheese
- thyme sprigs, for garnish
- 1 ½ cups grated cheese, gruyere, jack, or mozzerella cheese
Instructions
- 1
Preheat oven to 400F
- 2
Cut bread into 3/4 inch cubes and toast on baking sheet for 10 minutes
- 3
Cook bacon on foil-lined baking sheet for 20 minutes until crisp, then blot and cut into pieces
- 4
Heat oil in large skillet over medium high heat and saute onion rings for 2-3 minutes
- 5
Reduce heat to medium low and continue cooking onions until golden and tender, about 10 minutes
- 6
Heat butter in another large skillet over medium heat and cook mushrooms until tender, about 10 minutes
- 7
Add thyme, salt and pepper to mushrooms and cook off any liquid
- 8
Combine caramelized onions with mushroom mixture and set aside
- 9
Whisk eggs, milk, sour cream, salt and pepper in medium bowl
- 10
Combine toasted bread cubes, mushroom-onion mixture, bacon, grated cheese and 2/3 of goat cheese in large bowl
- 11
Pour egg mixture over bread mixture and stir gently
- 12
Let stand 5 minutes, then stir again
- 13
Pour into well greased 4 quart baking dish
- 14
Cover with foil and bake at 400F for 35 minutes
- 15
Uncover, reduce heat to 375F and bake 20-30 minutes until puffed and golden
- 16
Scatter remaining goat cheese on top during last 10 minutes
- 17
Garnish with thyme sprigs
Tips
Let the strata rest 5 minutes between stirring to ensure bread absorbs the custard evenly
Use day-old bread for better texture - fresh bread becomes too soggy while stale bread holds its shape
Cook mushrooms until all liquid evaporates to prevent a watery strata
Good to Know
refrigerate covered up to 3 days
assemble completely and refrigerate overnight before final baking
cut into squares and serve warm from baking dish
Common Mistakes
use day-old bread to avoid soggy texture
cook mushrooms until liquid evaporates to prevent watery results
let custard soak into bread before baking for even distribution
Substitutions
Dairy-Free Swaps
Gluten-Free Swaps
General Alternatives
FAQ
Can I make this completely ahead of time?
Yes, assemble the entire strata and refrigerate overnight. Add 5-10 minutes to the covered baking time if baking straight from the refrigerator.
What if I don't have goat cheese?
Substitute with cream cheese, ricotta, or feta cheese. Cream cheese provides similar creaminess while feta adds tangy flavor like goat cheese.
How long will leftovers keep?
Store covered in the refrigerator for up to 3 days. Reheat individual portions in the microwave or warm the whole dish in a 350F oven.