Christmas Miracle Breakfast Casserole

I have been trying to get my kids to eat breakfast casseroles for years. YEARS. Nobody wants to be in the kitchen cooking on festive holiday mornings, and these "take it out of the fridge and pop it in the oven" casseroles promise to solve that problem, but not if your family uniformly turns up their noses every time you present one. So I sat down with my kids and we looked at recipes. Lots and lots of recipes. We picked and chose our favorite ideas from various recipes, and I assembled the resulting concoction. It's not that different from other breakfast casseroles I have made for them in the past. But they ate it. Both of them. And they enjoyed it. Talk about a Christmas miracle. 

Edited to add: I made this for Thanksgiving 2015, cooked it in a 6-quart oval slow cooker for 10 hours on LOW, and woke up to a perfect breakfast.

1 26-oz bag frozen hash browns (I use Trader Joe's)

1 Tbsp butter

1 c diced onion

1 lb cremini mushrooms, sliced

12 eggs

1/2 c milk

1 tsp salt

1 tsp ground cumin

3/4 tsp ground coriander

1/2 tsp ancho chile powder

1/4 tsp ground black pepper

12 ozs grated pepper jack cheese

Butter a 9x13 casserole dish or the ceramic liner of a 6-quart oval slow cooker. Set aside.

Heat butter over medium heat in a large saute pan. Add onions; cook until softened and beginning to brown. Add mushrooms in batches, stirring as needed. Add spices; saute just until fragrant. Turn off heat. 

While vegetables cook, beat eggs and milk together. Place one-third of hash browns in bottom of prepared casserole. Top with half of sauteed vegetables, then a little less than half of cheese. Repeat this process with one-third of hash browns, the other half of sauteed vegetables, a little less than half of cheese, and the rest of the hash browns. Pour egg mixture atop vegetables, poking gently as needed to coat evenly. Top with the rest of the cheese.

I baked this in a casserole dish immediately after assembling it. It took 45 to 50 minutes at 375 degrees, the first half covered. This was much longer than I'd anticipated. Next time I'm going to try to cook it overnight in my slow cooker, which has a "keep warm" feature once the set time has elapsed. I'll start with 6 hours on HIGH, and we'll see how it goes.