vegetarian breakfast casserole strata with swiss chard on a blue plate

Vegetarian Breakfast Casserole with Swiss Chard and Gruyere

Swiss Chard and Gruyere Strata is a make-ahead vegetarian breakfast casserole that's perfect for feeding a crowd. Loaded with veggies, eggs, cheese, and crusty bread, this breakfast bake soaks overnight in your fridge and bakes up in the morning. Leftovers freeze like a dream, and this is also a fantastic packed lunch.

Course Breakfast
Cuisine American
Keyword Breakfast casserole, Strata
Prep Time 20 minutes
Cook Time 55 minutes
Total Time 1 hour 15 minutes
Servings 8
Calories 438 kcal
Author Katie Trant


  • 1 Tbsp 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 Tbsp smooth dijon mustard
  • cups milk
  • 1 tsp salt
  • freshly ground black pepper
US Customary - Metric


  1. Heat olive oil in a large skillet over medium-high heat.
  2. Add the onion, and sauté for about 3 minutes, until translucent.

  3. Add the Swiss chard, and sauté until wilted and the stems are slightly browned. Season with salt and pepper and remove from the heat.

  4. Generously butter a 9x13 casserole dish.
  5. Layer one-third of the bread cubes over the bottom of the dish. It won't fully cover the bottom, but this is ok.
  6. 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.
  7. Repeat these layers two more times.
  8. Whisk eggs together with Dijon mustard, then whisk in the milk, salt, and pepper.
  9. 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.

  10. When you're ready to bake, preheat the oven to 350°F /180°C.
  11. 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).
  12. Remove from the oven and let stand for 10 minutes before serving.

Recipe Notes

Nutrition Facts
Vegetarian Breakfast Casserole with Swiss Chard and Gruyere
Amount Per Serving
Calories 438 Calories from Fat 225
% Daily Value*
Fat 25g38%
Saturated Fat 12g60%
Cholesterol 293mg98%
Sodium 919mg38%
Potassium 325mg9%
Carbohydrates 23g8%
Fiber 1g4%
Sugar 6g7%
Protein 29g58%
Vitamin A 1268IU25%
Vitamin C 3mg4%
Calcium 623mg62%
Iron 3mg17%
* Percent Daily Values are based on a 2000 calorie diet.