Ham and Mushroom Egg Casserole with Challah and Fontina
This hearty breakfast casserole layers cubed challah bread with caramelized shallots, sautéed mushrooms, diced ham, and creamy fontina cheese, all bound together with a rich custard of eggs and half-and-half. The combination of sweet caramelized shallots and earthy mushrooms creates depth of flavor, while the challah bread adds a tender, slightly sweet base that soaks up the custard beautifully. Perfect for weekend brunch, holiday mornings, or feeding a crowd, this make-ahead friendly dish can be assembled the night before and baked fresh in the morning. The fontina cheese melts into creamy pockets throughout, and fresh thyme adds an aromatic herb note that complements the savory ham and vegetables.
Ingredients
- 3 tablespoons vegetable oil
- 1 cup shallots, sliced, about 3 medium
- 1 package (8 oz) mushrooms, sliced
- 6 cups challah bread, cubed 1-inchbrioche or thick white bread1:1bread
similar rich texture
- 2 cups fontina cheese, shredded, 8 ozgruyere or swiss1:1cheesedairy-free
nutty flavor profile
- 1 ½ cups cooked ham, diced
- 10 eggs
- 2 cups half-and-halfheavy cream1:1dairyadds dairy
richer result
- 2 teaspoons Dijon mustard
- 1 tablespoon fresh thyme leaves, finely chopped
- ½ teaspoon salt
- ½ teaspoon pepper
Instructions
- 1
Heat oven to 350°F and spray 13x9-inch baking dish with cooking spray
- 2
Heat 2 tablespoons oil in nonstick skillet over medium-high heat and cook shallots 4 to 6 minutes until starting to caramelize, then remove from skillet
- 3
Add remaining oil and mushrooms to same skillet and cook 4 to 6 minutes until tender and browned
- 4
Layer half the bread in baking dish, then add 1 1/2 cups cheese, shallots, mushrooms, ham and remaining bread
- 5
Beat eggs and half-and-half in large bowl, then beat in mustard, thyme, salt and pepper
- 6
Pour egg mixture over bread mixture, pressing down slightly, then sprinkle with remaining cheese
- 7
Bake 45 to 50 minutes until golden brown and center is just set
- 8
Let stand 15 minutes before serving
Tips
For best results, use day-old challah bread as it will absorb the custard better without becoming too soggy.
Caramelize the shallots slowly over medium heat for the sweetest flavor - don't rush this step as it adds important depth.
Let the casserole rest the full 15 minutes before cutting to allow the custard to set properly for clean slices.
Good to Know
Refrigerate leftovers up to 3 days in airtight container. Reheat individual portions in microwave or oven until heated through.
Assemble completely through step 5, cover tightly and refrigerate overnight. Add 10-15 minutes to baking time if baking from cold.
Cut into squares and serve warm. Pairs well with fresh fruit, coffee cake, or light salad for brunch.
Common Mistakes
Don't skip pressing the bread down into the custard or you'll have dry spots that don't set properly.
Avoid overbaking or the custard will become rubbery - center should be just set but still slightly jiggly.
Substitutions
Dairy-Free Swaps
nutty flavor profile
General Alternatives
similar rich texture
FAQ
Can I make this casserole ahead of time?
Yes, assemble completely through adding the egg mixture, cover and refrigerate overnight. Add 10-15 minutes to the baking time when cooking from cold.
What if I don't have challah bread?
Brioche works excellently as a substitute, or use thick slices of day-old white bread, French bread, or even croissants for similar rich texture.
How long will leftovers keep in the refrigerator?
Store covered in refrigerator for up to 3 days. Reheat individual portions in microwave for 1-2 minutes or in 300°F oven until warmed through.