Vegetarian Breakfast Casserole with Swiss Chard and Gruyere

Vegetarian breakfast casserole with Swiss chard andGruyere is a make-ahead strata that’s perfect for feeding a crowd. Cubes of crusty bread are layered with sautéed vegetables, eggs, milk, and plenty of cheese, soaked overnight, then baked in the morning into a savory breakfast. It reheats beautifully and makes a fantastic brunch centerpiece—or a stellar packed lunch.

Course Breakfast

Cuisine American

Diet Vegetarian

Keyword Breakfast casserole, Strata

Prep Time 20

Cook Time 55

Total Time 1 15

Servings

Calories 438kcal

Author Katie Trant

Ingredients

1 Tablespoon extra virgin olive oil
1 medium yellow onion diced
1 large bunch Swiss chard washed and roughly chopped
8 cups cubed whole grain bread in one-inch cubes I used a sourdough rye
2 cups coarsely grated gruyere
1 cup finely grated Parmesan cheese
9 large eggs
2 Tablespoons smooth dijon mustard
2¾ cups milk
1 teaspoon salt
freshly ground black pepper

US Customary - Metric

Instructions

Heat olive oil in a large skillet over medium-high heat.
1 Tablespoon extra virgin olive oil
Add the onion, and sauté for about 3 minutes, until translucent.
1 medium yellow onion
Add the Swiss chard, and sauté until wilted and the stems are slightly browned. Season with salt and pepper and remove from the heat.
1 large bunch Swiss chard
Generously butter a 9x13 casserole dish.
Layer one-third of the bread cubes over the bottom of the dish. It won't fully cover the bottom, but this is ok.
8 cups cubed whole grain bread in one-inch cubes
Layer one-third of the sautéd chard over top of the bread, followed by one-third of the gruyere, and one-third of the Parmesan.
2 cups coarsely grated gruyere, 1 cup finely grated Parmesan cheese
Repeat these layers two more times.
Whisk eggs together with Dijon mustard, then whisk in the milk, salt, and pepper.
9 large eggs, 2 Tablespoons smooth dijon mustard, 2¾ cups milk, 1 teaspoon salt, freshly ground black pepper
Pour the custard over top of the strata layers. Cover with plastic wrap, and set in the fridge overnight or for at least four hours, but up to one day.
When you're ready to bake, preheat the oven to 350°F /180°C.
Bake the strata for 45-55 minutes, until it is puffed and golden on top, and no longer so jiggly in the middle (a little jiggle is ok as it will continue to cook as it cools).
Remove from the oven and let stand for 10 minutes before serving.

Notes

If you don't have Swiss chard you can substitute another sturdy leafy green, such as kale, collard greens, or mustard greens.
Any sharp cheese can be used in place of the gruyere, but it really is delicious.
I don't have a lot of fridge space, so I often just soak on the counter for an hour before baking. This is totally fine.
Cooled strata can be sliced into squares, wrapped in foil, and frozen for quick and easy meals. They make for a great packed lunch.
Nutrition values are an estimate only.

Nutrition