Egg and Cheese Croissant Casserole with Gruyère and Sumac

By AislePrompt Editorial · Published 2026-05-28 · Updated 2026-05-28

How this recipe was made — this recipe was drafted by AislePrompt's AI-assisted pipeline from technique templates and USDA-sourced nutrition data, and published by AislePrompt Editorial — see how AislePrompt recipes are developed and reviewed.

An elevated brunch casserole with flaky croissants soaked in a spiced egg custard, layered with nutty Gruyère cheese and a hint of tangy sumac. This French-inspired brunch recipe, ready in about 60 minutes, combines large croissants, Gruyère cheese, large eggs into a breakfast that fuels the morning without the midday crash — make-ahead-friendly and balanced enough to anchor the first meal of the day. Each serving lands at about 460 calories and feeds 6, so it sits comfortably in a weekly breakfast rotation alongside fruit, yogurt, or coffee. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 15 min Cook: 45 min Serves 6 French cuisine 460 cal/serving

Build a week of meals around this recipe → Shop this recipe on Instacart → Shop equipment ↓

Ingredients

5, torn into 2-inch chunks large croissants
1 1/4 cups, shredded Gruyère cheese
7 large eggs
2 cups whole milk
1/2 cup heavy cream
1 1/2 tsp sumac
1 tsp salt
1/2 tsp black pepper
for greasing the baking dish butter

The 9x13 baking dish we’d bake this in → Best Bakeware for 2026: Top Picks + Buying Guide

Affiliate disclosure: AislePrompt may earn a commission on qualifying purchases made through Amazon links, at no additional cost to you. See our policy →

Equipment for this recipe

Tools this recipe's steps call for, with a link to each on Amazon.

More Bakeware & baking tools → Shop all kitchen tools →

Instructions

Step 1: Preheat oven to 350°F. Butter a 9x13-inch baking dish generously to prevent sticking.
Step 2: Spread 5 torn croissant pieces evenly in the baking dish and sprinkle 1 1/4 cups shredded Gruyère cheese evenly over the top.
Step 3: In a large mixing bowl, whisk together 7 large eggs, 2 cups whole milk, 1/2 cup heavy cream, 1 1/2 tsp sumac, 1 tsp salt, and 1/2 tsp black pepper until completely blended.
Step 4: Pour the egg mixture evenly over the croissant and cheese layers, gently pressing down with a spatula to submerge the croissants.
Step 5: Let the casserole sit for 10 minutes to allow the croissants to soak up the custard.
Step 6: Bake uncovered for 40-45 minutes until the top is puffed and golden and a knife inserted in the center comes out clean.
Step 7: Remove from oven and allow to cool for 5 minutes before slicing and serving warm.