01 -
Turn your oven to 175°C (350°F). Lay the croissant halves (cut side up) on a tray lined with parchment. Toast them in the oven for 10-12 minutes 'til they're golden. Tear them into large chunks once they're cool.
02 -
Spread the torn croissant pieces evenly inside a 9-by-13-inch dish.
03 -
Cook the chopped bacon in a pan over medium until crispy. Scoop it onto a plate lined with paper towels using a slotted spoon. Save 1 spoonful of the bacon grease in the pan.
04 -
Using the same pan with the left-over grease, toss in the onion or shallots with a little bit of salt and pepper. Let them cook for about 3-5 minutes until they soften and turn clear.
05 -
Scatter the cooked bacon, onions, and cheese over the croissant chunks in the dish. Give everything a light mix if you'd like.
06 -
In a medium bowl, combine the eggs, cream, milk, salt, and pepper. Whisk like crazy until it's all smooth. Pour this mixture evenly over the layers in the dish.
07 -
Put a cover on the dish, then stick it in the fridge for at least 4 hours but not more than 12 (to avoid sogginess).
08 -
Crank the oven to 175°C (350°F). Remove the dish's cover, place it on a baking sheet lined with foil (to catch drips), and bake for 45-50 minutes. The casserole should puff up and be golden on top.
09 -
Let it sit for about 10-15 minutes, then slice and enjoy.