Buttery Breakfast Casserole

Updated Feb 3, 2025

Total Time: 1.5 hours (plus 4 hours or overnight chilling)

Servings: 8–10 portions (adjusted from comments, serving size: 1 croissant, 2.5 oz sausage, 1.5 eggs, ½ cup dairy, 1.6 oz Gruyère per person)

Ingredients

• 1 pound croissants (≈5–7 croissants), split lengthwise

• 1 tablespoon extra-virgin olive oil (for browning), plus additional for baking dish

• 1 bunch scallions (6–7), white/light green parts thinly sliced (greens reserved for garnish)

• ¾ pound sweet Italian sausage, casings removed

• 2 teaspoons finely chopped fresh sage

• 8 large eggs

• 3 cups whole milk

• 1 cup heavy cream

• 8 ounces Gruyère, grated (≈2 cups) (reserve ½ cup for final topping)

• 1¼ teaspoons kosher salt

• 1 teaspoon freshly ground black pepper

Preparation

Step 1: Toast Croissants for Crisp Texture

Preheat oven to 500°F (260°C). Line a large baking sheet with parchment paper. Arrange croissants, cut-side up, and toast until golden-brown and crisp, 5–10 minutes. Monitor closely to prevent burning; the high heat ensures rapid browning. Let cool, then tear into 1.5–2-inch pieces.

Step 2: Sauté Sausage and Aromatics

In a medium skillet, heat olive oil over medium-high heat until shimmering. Add scallion whites/greens, sauté 1 minute until fragrant. Add sausage meat, breaking into crumbles with a fork, and cook 5 minutes until deeply browned. Drain excess fat (optional) and stir in sage; set aside.

Step 3: Mix Base Layers

In a large bowl, combine toasted croissants and browned sausage-scallion mixture. In a separate bowl, whisk eggs, milk, cream, 1.5 cups Gruyère, salt, and pepper until smooth (no egg whites).

Step 4: Assemble and Chill

Lightly grease a 9×13-inch baking dish. Transfer croissant-sausage mix, spread evenly. Pour custard over, pressing croissants to absorb liquid. Cover tightly with plastic wrap and refrigerate 4+ hours or overnight to allow flavors to meld and croissants to hydrate.

Step 5: Bake to Perfection

Preheat oven to 350°F (175°C). Uncover, sprinkle remaining ½ cup Gruyère on top. Bake 45 minutes until golden-brown and firm (toothpick inserted center comes out clean). Rest 10 minutes, then garnish with scallion greens.

Pro Tips

• Shortcuts: Use pre-toasted croissants or Trader Joe’s 3-packs; pre-grated Gruyère for convenience.

• Variations: Swap sausage for bacon/ham, Gruyère for Swiss/cheddar, add caramelized onions or mushrooms.

• Texture: For softer croissants, reduce chilling time to 2 hours; skip chilling for ultra-crisp bites.

Customer Reviews

• "This is the bomb! Stop criticizing—if you don’t like ingredients, don’t make it. Life’s too short for bad eggs."

• "Practice run with sweet sausage + Swiss was amazing! Quiche, veggie, or mushroom versions work too."

• "Added caramelized onions—now brunch staple. Trader Joe’s 3-pack croissants = perfection."

Note: Nutrition and portion adjustments reflect user comments for transparency.