Jiffy Cornbread Breakfast Casserole for a Brunch Crowd

Jiffy cornbread breakfast casserole is a savory, tender breakfast bake made with corn muffin mix, browned breakfast sausage, eggs, cheese, and vegetables. It brings the familiar flavor of cornbread together with a hearty egg casserole in one pan, making it an easy centerpiece for brunch or a weekend breakfast.

Ingredients

1 lb (454 g) bulk breakfast sausage
1/2 cup (75 g) finely diced yellow onion
1/2 cup (75 g) finely diced red or green bell pepper
1 box (8.5 oz / 241 g) Jiffy corn muffin mix
8 large eggs (about 400 g without shells)
1 cup (240 ml) whole milk
1/2 cup (120 g) sour cream
1 1/2 cups (170 g) shredded sharp cheddar cheese, divided
1 cup (150 g) corn kernels, thawed if frozen and patted dry
1/2 tsp (3 g) fine salt
1/4 tsp (0.5 g) black pepper
1 tsp (5 g) butter or neutral oil, for greasing the baking dish

Use plain corn kernels rather than creamed corn, which adds extra liquid and can make the center take longer to set. If you prefer a milder cheese, Monterey Jack works in place of cheddar. The sausage already brings seasoning, so the measured salt is intentionally modest; taste the cooked sausage before adding more.

Instructions

Heat the oven and prepare the pan. Set a rack in the center of the oven and preheat to 350°F (175°C). Grease a 9-by-13-inch (23-by-33-cm) baking dish with the butter or oil. Let frozen corn thaw and drain while you prepare the other ingredients. Dice the onion and pepper into small pieces so they soften evenly and are easy to portion in each serving.
Brown the sausage. Set a large skillet over medium heat and add the sausage, breaking it into small crumbles with a spoon. Cook for about 8–10 minutes, stirring and turning the pieces, until no pink remains and the sausage is browned. Check the thickest crumbles with a food thermometer: the USDA FSIS safe minimum temperature for ground meat, including ground pork sausage, is 160°F (71°C). Transfer the sausage to a plate with a slotted spoon. If the pan has more than about a tablespoon of grease, carefully spoon off the excess.
Soften the vegetables. Add the diced onion and bell pepper to the skillet. Cook for 3–4 minutes, stirring, until they begin to soften but still hold their shape. If the skillet is dry, add a teaspoon of water rather than extra grease. Remove the pan from the heat and let the vegetables cool for a few minutes; adding very hot vegetables directly to the eggs can start to set them.
Mix the batter and egg base. In a large bowl, whisk the eggs, milk, sour cream, salt, and black pepper until the mixture is smooth. Whisk in the corn muffin mix just until no large dry pockets remain; a few small lumps are fine. Fold in the cooked sausage, softened vegetables, corn, and 1 cup (115 g) of the cheddar. Avoid beating the batter for a long time, which can make the cornbread portion heavier.
Fill the dish and bake. Pour the mixture into the prepared dish and spread it into an even layer. Sprinkle the remaining 1/2 cup (55 g) cheddar over the top. Bake uncovered for 40–45 minutes, until the center is set and the top is golden at the edges. Check the center with a food thermometer; the USDA FSIS safe minimum temperature for an egg dish is 160°F (71°C). If the top browns before the center reaches that temperature, loosely cover the dish with foil and continue baking, checking again after 5 minutes.
Rest, then serve. Set the casserole on a heat-safe surface and leave it to rest for 10 minutes. This gives the egg custard time to settle, so the portions lift out more cleanly. Cut into eight squares and serve warm. The middle should be moist and tender, not liquid; a little softness from the corn muffin mix is normal.

Tips

Drain wet ingredients well. Excess grease, watery vegetables, or wet thawed corn can leave a greasy or loose layer at the bottom. Drain the sausage, pat the corn dry, and let sautéed vegetables cool briefly before mixing them into the eggs.
Keep the pieces small. Crumble the sausage finely and dice the pepper and onion into pieces around 1/4 inch (6 mm). Large chunks can make the casserole harder to slice and leave some portions with more filling than others.
Watch the center, not only the color. Oven temperatures and baking dishes vary. A browned top does not guarantee that the egg mixture has reached a safe temperature, so use an instant-read thermometer in the center. A glass dish may also need a few extra minutes compared with a metal pan.
Adjust the seasoning thoughtfully. Breakfast sausage and cheese can both be salty. If you use a particularly well-seasoned sausage, start with less salt or omit it, then add hot sauce or flaky salt at the table for anyone who wants more.

Serving Suggestions

Serve a square on its own for a filling breakfast, or pair it with fresh fruit to balance the savory sausage and rich cheese. A bowl of berries, orange segments, or sliced melon needs no extra cooking and is easy to set out for brunch. For a more substantial spread, add a green salad with a tart vinaigrette or a platter of sliced tomatoes and cucumbers.

Put salsa, hot sauce, and extra sour cream on the table rather than mixing them into the casserole. That lets each person season a serving without changing the texture of the whole pan. If you are serving several dishes, cut the casserole into smaller squares and keep them warm only briefly; for food safety, do not leave cooked eggs at room temperature for more than two hours.

Variations

Make it meat-free: Replace the sausage with 8 oz (225 g) chopped mushrooms. Cook them with the onion and pepper until their released liquid evaporates and the pieces begin to brown. Because mushrooms are less salty than sausage, taste the egg mixture and adjust the salt before baking. You can also use a plant-based sausage, following its package directions for browning.

Change the vegetables: Swap the bell pepper for 1 cup (about 100 g) chopped baby spinach, or use a mixture of diced red pepper and sliced scallions. Cook watery vegetables first so they do not release liquid in the casserole. A small can of drained diced green chiles, about 4 oz (113 g), adds mild heat and a tangy flavor; reduce the salt if the chiles are salted.

Make it spicier: Use pepper jack instead of cheddar, or add 1/4 tsp (about 0.5 g) cayenne to the egg mixture. For a less spicy option with a little extra flavor, use smoked paprika. Add seasonings a little at a time because the sausage may already contain pepper or chile.

Try a different cheese: Monterey Jack, Colby, or a cheddar-Jack blend can replace the sharp cheddar in the same quantity. Freshly shredded cheese melts smoothly, while pre-shredded cheese is convenient and works well here. Avoid adding too much extra cheese, since it can make the top oily and the slices difficult to lift.

Storage and Reheating

Let leftovers cool until they are no longer steaming, then refrigerate them in a covered, shallow container within 2 hours of baking. Store for 3–4 days. For easy portions, cut the casserole into squares before chilling, or transfer the pieces to a container with parchment between layers. Do not leave the baking dish on the counter all afternoon; cooked egg dishes need prompt refrigeration.

Reheat individual portions in the microwave, covered loosely, in 30-second bursts until hot throughout, turning the piece once if it heats unevenly. For a larger amount, place portions in an oven-safe dish, cover with foil, and warm at 325°F (165°C) until heated through. Check leftovers with a food thermometer: the USDA FSIS recommendation is to reheat leftovers to 165°F (74°C). Uncover for the final few minutes if you want to crisp the top again.

You can freeze baked portions for up to 2 months for best quality. Wrap each cooled square tightly or place it in a freezer-safe container, and thaw it overnight in the refrigerator before reheating. The texture may be slightly softer after freezing because eggs and corn muffin mix hold moisture, but the casserole remains convenient for a quick breakfast. Avoid freezing the unbaked mixture: the leavening in the mix may not perform as intended after a long freeze.

Frequently Asked Questions

Can I assemble this casserole the night before?

For the best cornbread texture, cook the sausage and vegetables ahead, refrigerate them, and mix the egg base with the corn muffin mix shortly before baking. The mix begins absorbing liquid once combined, so letting the full batter sit overnight can make the finished casserole denser. If you do assemble it ahead, cover and refrigerate promptly, then bake it chilled; allow extra time and check the center temperature rather than relying only on the clock.

Can I use a different size baking dish?

A 9-by-13-inch dish gives this batch enough surface area to cook evenly. A smaller, deeper dish will make a thicker casserole and require more baking time; a larger, shallower dish will cook faster and may be more delicate to serve. Whatever dish you use, leave room for the mixture to rise slightly and verify that the center reaches 160°F (71°C).

Why is my casserole soggy in the middle?

The most common causes are a center that has not finished baking, excess grease, or vegetables that released too much water. Return an undercooked casserole to the oven and cover the top loosely if it is already brown. Next time, drain the sausage well, pat thawed corn dry, and cook mushrooms or other watery vegetables until their liquid has evaporated.

Can I use homemade cornbread mix instead of Jiffy?

Yes, but use a homemade corn muffin mix that makes roughly the same amount as one 8.5 oz (241 g) box, and account for any sugar, salt, or leavening already included. This recipe is designed around a prepared dry mix, not baked cornbread. Replacing it with crumbled cooked cornbread changes the balance of liquid and can produce a more bread-pudding-like texture.

How do I know when the casserole is done without overbaking it?

Look for a center that no longer jiggles like liquid when the pan is moved gently, then confirm the temperature at the center with a food thermometer. The required safe minimum for this egg dish is 160°F (71°C). Resting it for 10 minutes after baking helps the pieces hold their shape; it should not be used as a substitute for cooking the center to a safe temperature.

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Safety notes: safe minimum internal temperatures from USDA FSIS; raw and undercooked fish guidance from the U.S. FDA. Food safety notes

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