Leftover Ham Breakfast Casserole Recipe

This Leftover Ham Breakfast Casserole is the cozy, crowd-pleasing answer to “what do I do with all this ham?” Soft bread cubes soak up a rich, savory egg mixture, while little pockets of smoky ham, melted cheese, and sweet sautéed onions turn every bite into comfort food. The top bakes up golden and slightly crisp, with a fluffy, custardy center that feels like a cross between quiche and strata. It’s perfect for lazy weekends, holiday brunch, or busy mornings because you can assemble it ahead and simply bake when you’re ready to eat.

This casserole is ideal for the morning after a big holiday dinner when you want something hearty but easy. You can assemble it the night before, cover, and bake straight from the fridge, or let it rest for just 20–30 minutes before baking. Swap bread for hash browns, use any melting cheese you have, and toss in extra veggies like spinach or mushrooms. Serve it with fresh fruit, a simple green salad, or toast to round out the meal.

Ingredients

Here’s everything you need to turn leftover ham into a warm, cheesy breakfast bake everyone will want seconds of.

• Day-old crusty bread, cut into 1-inch cubes – 8 cups (about 300–350 g)
• Cooked leftover ham, diced – 2 cups
• Shredded cheddar cheese – 1 cup
• Shredded mozzarella or Swiss cheese – 1 cup
• Small yellow onion, finely diced – 1 (about ½ cup)
• Red or green bell pepper, diced – ½ cup (optional but recommended)
• Unsalted butter – 2 tablespoons (for greasing and sautéing)
• Large eggs – 10
• Milk – 1½ cups (375 ml)
• Heavy cream or half-and-half – ½ cup (125 ml)
• Dijon mustard – 1 teaspoon
• Garlic powder – ½ teaspoon
• Salt – 1 teaspoon (adjust to taste, depending on how salty your ham is)
• Black pepper – ½ teaspoon
• Dried thyme or dried parsley – ½ teaspoon
• Fresh chopped chives or parsley, for garnish – 2 tablespoons (optional)

Servings

This recipe makes about 8 generous portions when baked in a standard 9×13-inch (23×33 cm) dish. It comfortably serves 6–8 people as a main breakfast or brunch, or up to 10 if served alongside other dishes.

How to Make It

Prep the pan and sauté the veggies

Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish with a little butter. In a small skillet, melt the remaining butter over medium heat and sauté the diced onion and bell pepper for 3–5 minutes until softened and fragrant. Let cool slightly.

Layer the bread, ham, veggies, and cheese

Spread the bread cubes evenly in the greased baking dish. Scatter the diced ham over the bread. Spoon the sautéed onion and pepper mixture evenly on top. Sprinkle both cheeses over everything, making sure the surface is mostly covered.

Make the egg mixture

In a large mixing bowl, whisk together the eggs, milk, cream, Dijon mustard, garlic powder, salt, black pepper, and dried thyme or parsley until smooth and well combined. Make sure the yolks are fully broken and the seasoning is evenly dispersed.

Pour and soak

Slowly pour the egg mixture over the bread, ham, and cheese, making sure all areas are moistened. Use a spatula to gently press down the bread so it absorbs the liquid. Let the casserole sit for at least 20–30 minutes at room temperature, or cover and refrigerate for up to 12 hours for an overnight bake.

Bake until puffed and golden

If chilled, let the casserole sit at room temperature for about 15 minutes while the oven heats. Bake uncovered for 40–50 minutes, or until the top is golden, the center is set, and a knife inserted in the middle comes out mostly clean without runny egg.

Rest, garnish, and serve

Remove the casserole from the oven and let it rest for 10 minutes to set and make slicing easier. Sprinkle with chopped chives or parsley, cut into squares, and serve warm.

Pro Tip

For the best texture, use day-old or slightly dried bread so it can soak up the egg mixture without turning mushy. Overnight chilling gives extra flavor.

FAQs

Q1. Can I make this casserole the night before?
A1. Yes. Assemble fully, cover tightly, and refrigerate up to 12 hours. Let sit at room temperature about 15 minutes while the oven heats, then bake.

Q2. How long does leftover casserole keep in the fridge?
A2. Store cooled leftovers in an airtight container in the refrigerator for up to 3–4 days. Reheat individual pieces in the microwave or oven until hot.

Q3. Can I freeze this breakfast casserole?
A3. Yes. Bake, cool completely, then wrap tightly and freeze up to 2 months. Thaw overnight in the fridge and reheat, covered, at 325°F (165°C) until warmed through.

Q4. What can I use instead of bread?
A4. You can substitute frozen shredded hash browns (thawed and patted dry) or diced cooked potatoes. The texture will be slightly different but still delicious.

Q5. How can I make this recipe lighter?
A5. Use lean ham, low-fat milk, and reduce the cheese slightly. You can also add extra vegetables like spinach, mushrooms, or tomatoes to bulk it up.

Q6. Can I halve the recipe?
A6. Yes. Halve all ingredients and bake in an 8×8-inch dish. The baking time will be slightly shorter; start checking around 30–35 minutes.