Hash Brown Breakfast Casserole takes everything people love about a classic diner breakfast—crispy potatoes, savory sausage or ham, fluffy eggs, and gooey cheese—and bakes it into one easy, crowd‑pleasing casserole.
Frozen shredded or diced hash browns form the base, then you layer on cooked sausage or ham and a generous handful of cheese before pouring a simple egg and milk mixture over the top. It bakes up golden and set, with a tender middle and lightly crisp edges, and can be customized with veggies or different meats based on what you have. Best of all, it can be prepped ahead so your morning is practically hands‑off.
Equipment
- 9×13‑inch (or similar 3–4 quart) baking dish, well greased.
- Large skillet for browning sausage and sautéing any vegetables.
- Large mixing bowl for whisking eggs and milk.
- Whisk, wooden spoon or spatula, and measuring cups/spoons.
- Plastic wrap or foil if assembling overnight.
Ingredients
This template follows the “sausage + hash browns + eggs + cheese” style most popular with classic recipes.
- 1 lb (450 g) breakfast sausage (bulk or casings removed) OR about 2 cups diced cooked ham.
- 20–30 oz (about 600–850 g) frozen hash browns, shredded or diced, thawed or mostly thawed.
- ¼–½ cup finely diced onion.
- ½ red bell pepper, diced (optional).
- ½ green bell pepper, diced (optional).
- 2–3 cups (about 200–300 g) shredded cheese, divided (cheddar, Colby Jack, Mexican blend, or similar).
- 8–12 large eggs, depending on how eggy you like it (10–12 for a thicker, custardy casserole).
- 1½–2 cups (360–480 ml) milk, half‑and‑half, or evaporated milk.
- ½–1 teaspoon salt, to taste (go lighter if sausage and cheese are salty).
- ½ teaspoon black pepper.
- ½ teaspoon garlic powder.
- ½ teaspoon onion powder.
- ¼ teaspoon dry mustard (optional, adds subtle tang).
- Cooking spray or butter, for greasing the dish.
Optional add‑ins or toppings: sliced green onions, chopped spinach, mushrooms, bacon bits, hot sauce, salsa.
Instructions And Steps
Start by prepping the base and the meat. Grease the 9×13‑inch baking dish generously with cooking spray or butter so the hash browns and egg mixture don’t stick. If your hash browns are frozen solid, thaw them in the fridge or at room temperature until they’re mostly thawed and easy to spread, then pat them dry with paper towels to remove excess moisture.
In a large skillet over medium‑high heat, cook the breakfast sausage, breaking it into crumbles with a spoon as it browns. When it’s no longer pink, drain off any excess grease. If you’re using onion and bell peppers, add them to the skillet with the sausage partway through cooking and sauté until softened and fragrant. Remove the skillet from the heat and let the sausage mixture cool slightly while you assemble the rest.
Spread the thawed hash browns evenly over the bottom of the prepared baking dish, breaking up any clumps so you have a uniform layer. Many recipes simply layer them in frozen and let them cook in the oven, but starting from at least partially thawed potatoes promotes more even cooking and better texture.
Sprinkle the cooked sausage (or diced ham) and any sautéed onions and peppers evenly over the hash browns so every bite gets some of each component. Scatter about two‑thirds of the shredded cheese over this layer, reserving the remaining cheese for topping later.
In a large mixing bowl, crack in the eggs and whisk until yolks and whites are completely blended. Add the milk or half‑and‑half, salt, pepper, garlic powder, onion powder, and dry mustard if using, then whisk again until the mixture is smooth and the seasonings are evenly distributed. Taste a tiny bit (or adjust by experience), remembering that sausage and cheese add additional salt.
Slowly pour the egg mixture evenly over the hash brown, sausage, and cheese layers in the baking dish. Use the back of a spoon or spatula to gently press down on the top so the egg mixture seeps through and all the hash browns and sausage are moistened; this helps prevent dry pockets.
If you plan to bake the casserole right away, preheat the oven to 350°F (175°C) while the assembled dish rests for about 10–15 minutes. This brief rest allows the hash browns to start absorbing the egg mixture and helps everything bake more evenly. If you want an overnight version, cover the dish tightly with plastic wrap or foil and refrigerate for at least 2 hours and up to 12 hours.
When you’re ready to bake, remove any plastic wrap, and if the casserole is coming directly from the fridge, let it sit on the counter for 15–20 minutes while you preheat the oven to 350°F. Place the casserole on the middle rack and bake uncovered for 40–60 minutes, depending on your oven, pan, and how many eggs you used.
Check for doneness by gently jiggling the pan: the center should be set and no longer runny, and a knife or toothpick inserted in the middle should come out without liquid egg clinging to it. The top should be lightly golden and the edges may be a bit more browned and crisp. If the top browns too quickly while the center is still loose, tent the casserole lightly with foil for the remainder of the bake.
About 10–15 minutes before it’s fully done, sprinkle the remaining cheese evenly over the top and return the casserole to the oven so the cheese melts into a bubbly, gooey layer. Once the eggs are fully set and the cheese is melted, remove the casserole from the oven and let it rest for 10 minutes before slicing. This resting time helps firm up the egg mixture and makes for cleaner squares.
Slice the Hash Brown Breakfast Casserole into squares and serve warm, making sure each portion includes plenty of hash browns, sausage or ham, and cheesy egg. Garnish with sliced green onions or a spoonful of salsa, if desired, and serve with fruit or pastries on the side for a complete brunch spread.
Tips And Tricks
Patting the hash browns dry and starting from at least partially thawed potatoes help prevent an overly wet casserole and encourage the bottom to cook through without going mushy. If you like a crisper bottom layer, you can pre‑bake the hash browns alone with a little oil or butter in the pan for 10–15 minutes before adding the sausage and pouring on the egg mixture.
Brown the sausage thoroughly and drain it well so excess fat doesn’t pool in the bottom of the dish. Choosing a flavorful sausage (sage, spicy, or maple) adds a lot of character; just remember sweeter sausages may pair better with extra black pepper and less extra salt.
Use enough eggs and dairy to fully saturate the base; too little liquid will leave dry patches of hash browns and a thin, uneven egg layer. Most recipes follow a rough ratio of 8–12 eggs and 1½–2 cups milk for a full 9×13‑inch pan, scaling up eggs and milk as you add more mix‑ins.
Whisk the egg mixture well so the seasoning is evenly distributed—no one wants a bite that’s all pepper or salt. You can mix the eggs in the same bowl that held the hash browns and sausage (after emptying it into the pan) to cut down on dishes.
Overbaking can make the casserole dry and rubbery, so start checking on the early side of the bake‑time range. The center should be just set; it will continue to firm up slightly as it rests out of the oven.
This casserole reheats very well, making it great for meal prep. Store leftovers tightly covered in the fridge and warm individual slices in the microwave or oven; adding a tiny splash of milk or covering with foil keeps them from drying out.
Variations
Swap the sausage for diced ham, bacon, or a combination of meats to change the flavor profile. Ham pairs nicely with Swiss or Gruyère cheese, while bacon works well with sharp cheddar or pepper jack. You can also use chicken or turkey sausage if you want to lighten things up without sacrificing protein.
Add vegetables to make the casserole more colorful and nutritious. Popular additions include spinach, mushrooms, broccoli florets, jalapeños, and diced tomatoes; just sauté moisture‑heavy veggies briefly first so they don’t water down the egg mixture. Stir them in with the sausage or layer them over the hash browns before adding the egg mixture.
Make a Tex‑Mex version by using spicy sausage or chorizo, adding green chiles, and swapping in a Mexican cheese blend; serve with salsa, avocado, and cilantro. Or go Mediterranean with feta, spinach, sun‑dried tomatoes, and Italian sausage, seasoning the eggs with oregano and basil.
For a richer holiday brunch casserole, increase the cheese and use half‑and‑half or evaporated milk instead of regular milk; this gives a more custard‑like interior that feels extra indulgent. You can also assemble the entire casserole the night before, refrigerate, then bake straight from the fridge (with a little extra time) so your morning is stress‑free.
To make it gluten‑free, simply ensure your sausage and any seasoning blends are gluten‑free and use naturally gluten‑free hash browns; the rest of the ingredients are typically safe. Serve with naturally gluten‑free sides like fruit salad or yogurt, and you’ve got an easy, inclusive breakfast that still tastes like pure comfort.
