Storage Tips

Freezer: Casserole may be frozen up to 3 months in a zip-top bag or wrapped tightly in foil. For individual servings, cut cooled casserole into squares, wrap each in plastic then foil, and store in a large bag; reheat straight from frozen 20 minutes at 350 °F.

Refrigerator: Baked casserole keeps 4 days covered. Reheat squares in toaster oven for best texture; microwave if you’re in a rush.

Make-ahead (no freezer): Assemble the night before, cover tightly, and refrigerate up to 18 hours. Bake 55 minutes covered, 15 uncovered.

Frequently Asked Questions

Can I use egg whites only?

You can substitute up to half the eggs with egg whites, but omitting yolks entirely yields a rubbery texture. Keep at least 4 yolks for richness.

Do I have to roast red peppers myself?

Jarred roasted peppers work beautifully; just blot them well. In a pinch, diced raw bell pepper sautéed 3 minutes with the onion is fine.

Can I bake in a glass dish straight from frozen?

Glass can thermal-shock. Thaw in refrigerator overnight, or start in a cold oven set to 325 °F for 15 minutes before raising to 375 °F.

How do I know when it’s done?

Center should puff slightly and an instant-read thermometer inserted at the thickest point should read 165 °F. A little wobble is perfect; slosh means bake 5–10 minutes more.

Can I double the recipe?

Absolutely. Use two 9×13 pans or one deep half-sheet (13×18); increase covered bake time by 15 minutes. Rotate pans halfway for even browning.

Is this gluten-free?

Swap in a hearty gluten-free bread (cubed and dried). All other ingredients are naturally GF; check sausage labels for wheat fillers.

breakfast

Pin Recipe

Freezer-Friendly Breakfast Casserole for Winter Brunch

Love this? Pin it for later! There’s something magical about pulling a golden, bubbling breakfast casserole out of the oven on a frosty January morning—especially when all the…

Prep—

Cook—

Serves—

Ingredients

10 cups cubed sourdough bread (¾-inch cubes, day-old)
1 pound breakfast sausage (pork or turkey)
1 medium yellow onion, diced
2 cloves garlic, minced
1 cup diced roasted red peppers, patted dry
2 cups packed baby spinach (or thawed frozen, squeezed dry)
8 large eggs
2 cups half-and-half
1 Tbsp Dijon mustard
1 tsp kosher salt
½ tsp black pepper
⅛ tsp ground nutmeg
2 cups shredded sharp cheddar, divided
Cooking spray & parchment

Instructions

Brown sausage & onion: In a skillet over medium heat, cook sausage 5 min; add onion 4 min; add garlic 30 sec. Cool.
Prep pan: Grease 9×13 pan; line with parchment sling.
Layer: Half bread cubes → sausage mixture → peppers & spinach → remaining bread.
Whisk custard: Beat eggs, half-and-half, Dijon, salt, pepper, nutmeg.
Pour & top: Soak bread; sprinkle with ½ cup cheddar.
Flash-freeze: Wrap, freeze solid, then bag. OR bake now: 375 °F covered 55 min, uncovered 15 min until 165 °F center.