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Overnight Croque Monsieur Casserole Recipe

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★★★★★

4.4 from 64 reviews

This Overnight Croque Monsieur Casserole is a delightful twist on the classic French sandwich, layered with butter bread, Canadian bacon, Gruyere cheese, and a flavorful custard infused with garlic, onions, and thyme. Prepared the night before and baked to golden perfection, this savory casserole offers a rich and comforting breakfast or brunch option that serves a crowd.

Ingredients

Scale

For the Custard and Flavor Base

  • 1 Tablespoon Unsalted Butter, plus more to coat pan
  • 1 Yellow Onion, roughly chopped (about 1 1/2 cups)
  • 4 Cloves Garlic, thinly sliced
  • Salt and Pepper, to taste
  • 1 Tablespoon Fresh Thyme, roughly chopped, plus one teaspoon for garnish
  • 8 Large Eggs
  • 1 1/2 Cups Half-and-Half
  • 2 Tablespoons Dijon Mustard
  • 1/2 Teaspoon Hot Sauce, plus more for garnish
  • 1 1/2 Teaspoons Kosher Salt

Main Ingredients

  • 1 Loaf Martin’s Old-Fashioned Real Butter Bread, stale or toasted, cut into thick cubes
  • 2 Cups Gruyere Cheese, shredded (about 4.5 ounces)
  • 1/2 Pound Canadian Bacon, cut into 1/2-inch dice
  • 1/4 Cup Parmesan Cheese, finely grated (about 1 ounce)

Instructions

  1. Prepare the Baking Dish: Coat a 3-quart (13×9-inch) baking dish generously with butter and set aside to prevent sticking during baking.
  2. Sauté Aromatics: Heat a large frying pan over medium heat and melt the tablespoon of butter until slightly frothy. Add the chopped onion, season with salt, and cook for about 3 to 4 minutes until softened. Then add the garlic slices, season with salt and pepper, and cook for another 1 minute until fragrant. Remove from heat and stir in the chopped fresh thyme for added flavor.
  3. Mix Custard: In a large bowl, whisk together the eggs, half-and-half, Dijon mustard, hot sauce, and kosher salt until the mixture is smooth and well combined.
  4. Assemble the Casserole: Arrange half of the thick bread cubes evenly at the bottom of the prepared baking dish. Sprinkle half of the shredded Gruyere, followed by half of the sautéed onion-garlic mixture, and half of the diced Canadian bacon. Repeat the layering process with the remaining bread, onion mixture, ham, and Gruyere cheese. Pour the egg custard evenly over the assembled layers.
  5. Soak Overnight: Press down firmly on the bread to ensure it is fully submerged in the egg custard. Cover the dish with plastic wrap and place a heavy plate on top to weigh it down. Refrigerate for 3 to 12 hours to let the flavors meld and the bread soak thoroughly.
  6. Bake Covered: When ready to bake, remove the plastic wrap and weight from the casserole. Cover the dish with aluminum foil and place it in the oven on the middle rack. Set the oven temperature to 325°F (you do not need to preheat) and bake for 35 minutes to gently cook the custard.
  7. Finish Baking and Brown: Remove the foil, sprinkle the finely grated Parmesan cheese over the top of the casserole, and increase the oven temperature to 375°F. Bake uncovered for another 10 to 15 minutes until the top is golden brown and bubbly.
  8. Garnish and Serve: Take the casserole out of the oven and sprinkle the remaining fresh thyme on top. Let it cool for at least 5 minutes before serving. Offer hot sauce on the side for an optional spicy kick.

Notes

  • For best results, use stale or toasted butter bread to prevent the casserole from becoming too soggy.
  • The casserole can be refrigerated overnight and baked the next morning for a convenient make-ahead breakfast or brunch.
  • You can substitute Canadian bacon with smoked ham or regular cooked ham according to preference.
  • Adjust the amount of hot sauce to taste for milder or spicier casseroles.
  • Leftovers can be stored in an airtight container in the refrigerator for up to 3 days and reheated gently in the oven.

Keywords: Overnight Croque Monsieur, Breakfast Casserole, French Breakfast, Gruyere Casserole, Make Ahead Breakfast

Find it online: https://messykitchenmagic.com/overnight-croque-monsieur-casserole-recipe/