Potato Egg Casserole: Easy Breakfast Bake

This potato egg casserole uses 3 cups of pre-cooked potatoes, six eggs, and ½ cup of milk for a firm, sliceable texture. Bake it in an 8-inch square pan at 375°F for 30 to 38 minutes, then rest it before cutting.

The base stays neutral, so you can add sautéed vegetables, herbs, or cheese without changing the simple egg-to-liquid ratio. It makes six servings for breakfast, brunch, or an easy make-ahead meal.

Potato Egg Casserole: Base Ingredients and Optional Add-Ins

Gather the ingredients before assembling. The potatoes should be cooked, cooled slightly, and cut into small, even pieces.

3 cups cooked potatoes: Use peeled or unpeeled potatoes cut into ½-inch cubes. Waxy or all-purpose varieties hold their shape well.
6 large eggs
½ cup milk: Whole milk, 2% milk, or unsweetened plain plant milk works well.
½ teaspoon fine salt
¼ teaspoon black pepper
1 tablespoon butter or olive oil: Use it to grease the pan or sauté vegetables.

This six-egg-to-½-cup-milk ratio creates a casserole that is tender but firm enough to slice. Avoid adding extra milk unless you also increase the eggs, because too much liquid can leave the center wet.

Optional add-ins can include up to 1 cup of cooked vegetables, such as diced bell pepper, onion, mushrooms, spinach, broccoli, or zucchini. Add ½ cup shredded cheddar, Monterey Jack, mozzarella, or another melting cheese if desired. Cheese is optional, not required for the base recipe.

Fresh herbs also work well. Try 1 tablespoon of chopped parsley, chives, basil, or cilantro. Cooked bacon, sausage, or ham can replace some of the vegetables, but keep the total add-ins to about 1½ cups so the eggs can bind everything together.

Pre-Cook the Potatoes for an Egg and Potato Casserole

Pre-cooking gives the potatoes a soft interior and prevents the egg mixture from overbaking while the potatoes finish. You can boil, steam, roast, or microwave them before assembling the casserole.

Peel the potatoes if preferred, then cut them into ½-inch cubes. You need about 3 cups of cooked potatoes.
To boil them, place the cubes in salted water and simmer for 7 to 10 minutes, until a fork enters easily but the pieces do not fall apart.
Drain the potatoes thoroughly and let them steam-dry for 5 minutes. Excess water can make the finished bake loose.
For more flavor, sauté the drained potatoes in 1 teaspoon of oil for 3 to 5 minutes, until lightly golden.

Roasted potatoes are another good option. Toss the cubes with a little oil and roast at 425°F for about 20 minutes, stirring once, until tender. Leftover roasted or boiled potatoes can go straight into the recipe after being cut into bite-size pieces.

If using vegetables, cook them before adding them. Sauté onions, peppers, mushrooms, or zucchini until tender and any visible moisture has evaporated. Wilt spinach, then squeeze it dry. This step prevents watery pockets in the egg and potato casserole.

Assemble the Egg and Potato Bake

Heat the oven to 375°F. Grease an 8-inch square baking dish with butter or oil. A 9-inch round dish with a similar volume also works, though the baking time may vary slightly.

Spread the cooked potatoes evenly across the bottom of the prepared pan.
Scatter the cooked vegetables, meat, herbs, or other add-ins over the potatoes. If using cheese, reserve a small handful for the top.
Whisk the eggs, milk, salt, and pepper in a medium bowl until the yolks and whites are fully combined. Do not whip in excessive air.
Pour the egg mixture slowly over the potatoes and add-ins. Tilt the pan gently so the liquid reaches the corners.
Sprinkle the reserved cheese over the surface, if using.

For the most even slices, keep the potatoes in one layer rather than piling them in the center. Press them down lightly, but do not compact them tightly. The egg mixture should surround the potatoes without completely covering a thick mound of fillings.

Assemble the egg and potato bake just before baking when possible. If you prepare it ahead, cover and refrigerate it for up to 12 hours. Let the cold dish sit at room temperature while the oven heats, and expect it to need a few extra minutes in the oven.

Bake, Rest, and Slice an Egg and Potato Breakfast Casserole

Bake the dish uncovered at 375°F for 30 to 38 minutes. Begin checking at 30 minutes, especially if the potatoes and vegetables were still warm when assembled.

The casserole is done when the edges are lightly puffed and golden, the surface looks set, and the center no longer appears wet. A gentle shake should produce only a slight, uniform quiver. For a more precise check, insert a thin knife near the center. It should come out mostly clean, with moist crumbs but no liquid egg.

If the center still looks loose after 38 minutes, continue baking in 3- to 5-minute increments. If the top browns before the middle sets, loosely cover the dish with foil. Avoid overbaking, which can make the eggs rubbery and cause the potatoes to dry out.

Transfer the baked casserole to a cooling rack and rest it for 10 minutes. This allows the eggs to finish setting and makes cleaner slices. Cut into six portions with a sharp knife, wiping the blade between cuts if needed.

Serve the egg and potato breakfast casserole warm with fruit, toast, salsa, or a simple green salad. Refrigerate leftovers in a covered container for up to four days. Reheat individual portions in the microwave in short intervals, or warm them in a 325°F oven until heated through.