Ingredients

A splash of extra virgin olive oil

6-8 ounces plant-based sausage (optional)

1 1/2 tablespoons Dijon-style mustard

1/4 teaspoon cayenne powder

1/2 teaspoon fine grain sea salt

2 cups milk, oat milk, or other plant-based milk

8 eggs

2 large bagels, torn into 1 1/2-inch segments

1 1/2 cups Gruyere cheese, grated

4 ounces Boursin cheese, feta, goat cheese, or cream cheese

3 tablespoons everything bagel seasoning

Instructions

Step 1: Preheat your oven to 350°F with a rack positioned in the center. Lightly oil a 9×13-inch baking dish or a similar sized dish.

Step 2: If using plant-based sausage, cook it according to the package instructions in a small amount of oil until browned on both sides. Remove and place on paper towels to cool slightly, then crumble and set aside.

Step 3: In a large bowl, whisk together the Dijon mustard, cayenne powder, sea salt, milk, and eggs until well combined.

Step 4: Add half of the grated Gruyere, the torn bagel pieces, and the cooked sausage to the egg mixture. Toss gently to coat everything evenly.

Step 5: Pour the mixture into the prepared baking dish. Sprinkle the remaining Gruyere cheese over the top, then dot with crumbled Boursin (or your choice of soft cheese).

Step 6: At this point, you can bake immediately or cover and refrigerate the casserole overnight for convenience.

Step 7: When ready to bake, sprinkle the casserole evenly with everything bagel seasoning. Cover the dish with foil and poke a few holes in the foil with a fork to allow steam to escape.

Step 8: Bake covered for 45 minutes. Carefully remove the foil and continue baking for another 30-40 minutes, or longer if baking directly from the refrigerator. The casserole is done when it is golden and set in the center.

Step 9: Let the casserole cool for 5-10 minutes before slicing and serving.

Tips & Variations

For extra flavor, toast the bagel pieces lightly before mixing them into the casserole to add crunch.

Swap the plant-based sausage for cooked bacon or breakfast sausage if you prefer a non-vegan option.

Add chopped fresh herbs like chives or parsley for a fresh pop of color and taste.

If you can’t find everything bagel seasoning, mix sesame seeds, poppy seeds, dried minced garlic, onion flakes, and salt as a homemade substitute.

Storage

Store leftover casserole covered in the refrigerator for up to 3 days. Reheat individual portions in the microwave or warm the entire dish in a 350°F oven until heated through. This casserole also freezes well; wrap tightly and freeze for up to 1 month. Thaw overnight in the fridge before reheating.

FAQs

Can I make this casserole without the plant-based sausage?

Yes, you can omit the sausage entirely for a vegetarian version or substitute with other proteins like cooked bacon or ham according to your preference.

Can I prepare the casserole the night before?

Absolutely! Mixing the casserole and refrigerating it overnight allows the flavors to meld beautifully and makes morning preparation quicker. Just add the everything bagel seasoning right before baking.