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Slice of Cousin Betty's Easy Overnight Breakfast Treat Casserole | A Reinvented Mom #overnightbreakfastcasserole
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5 from 2 votes

Cousin Betty's Best: Easy Overnight Breakfast Treat Casserole

Break out of the breakfast casserole rut. Surprise ingredients separate this make-ahead overnight breakfast casserole from the pack.
Prep Time20 mins
Cook Time1 hr
Refrigeration8 hrs
Total Time1 hr 20 mins
Course: Breakfast, Brunch
Cuisine: American
Keyword: easy breakfast casserole, make ahead breakfast casserole, overnight breakfast casserole
Servings: 12
Calories: 263kcal
Author: Lori


  • 4 slices bread
  • 1 tsp. dry mustard
  • 5 eggs
  • 1 1/2 cups milk
  • 1/2 tsp. salt
  • 1/4 tsp. ground black pepper
  • 1 pound breakfast sausage cooked
  • 1 can cream of mushroom soup undiluted
  • 2 cups shredded cheddar cheese divided use
  • 1/2 tsp. oregano


  • Lightly coat a 9x13 casserole dish with non-stick spray.
  • Cube the bread and place in the prepared casserole dish.
  • Sprinkle dry mustard over cubed bread.
  • Mix eggs, milk, salt and pepper together in a small bowl. Pour over bread.
  • Sprinkle 1 cup cheese over egg & bread mixture.
  • Layer cooked sausage over eggs, bread & cheese.
  • Top with undiluted mushroom soup.
  • Cover with remaining cup of shredded cheese.
  • Sprinkle oregano over top of casserole.
  • Cover and refrigerate overnight.
  • Preheat oven to 350 degrees. Remove casserole from refrigerator and set on counter until oven is ready.
  • Cover dish with foil and bake for 1 hour.


  • For crispier top, remove foil for last 1/2 hour of baking.
  • I use 2% milk in this recipe. For a richer casserole, use whole milk or half & half.
  • Refrigerate leftovers (if you have any!).
  • Nutritional information is provided as a reference only.


Calories: 263kcal | Carbohydrates: 6g | Protein: 14g | Fat: 19g | Saturated Fat: 8g | Cholesterol: 118mg | Sodium: 525mg | Potassium: 197mg | Sugar: 2g | Vitamin A: 365IU | Vitamin C: 0.2mg | Calcium: 201mg | Iron: 1.3mg