Step 1

Cook the bacon in a large skillet over medium heat until brown and crispy, about 8 minutes. Using a slotted spoon, transfer the bacon to a paper-toweled lined plate and set aside. Pour off extra grease, leaving about 2 tablespoons in the pan.

Step 2

Turn the heat up to medium-high and add the onions and red pepper flakes. Sauté until softened, about 3-4 minutes. Stir in the peppers, kale, and garlic and cook another 1-2 minutes, until the kale has wilted, seasoning lightly with salt and pepper while it cooks. Set aside. (Freezing instructions begin here.)

Step 3

Spray a 6-quart slow cooker insert generously with cooking spray. Layer 1 1/2 cups of the hash browns, 1/2 of the bacon, half of the veggie mixture, 1/4 cup Parmesan, and 1 cup Gruyere, and then repeat with the remaining hash browns, bacon, veggies, and cheeses.

Step 4

In a large mixing bowl, whisk together eggs, milk, 1/4 teaspoon salt, and 1/4 teaspoon black pepper. Pour over the other ingredients in the slow cooker. (Note: The casserole can sit in the refrigerator for up to 3 days at this point.)

Step 5

Cover and cook on Low for 4 hours, or until the center is set.

Step 6

Dab off any moisture from the top with a paper towel. Taste and season with more salt and pepper, as needed. Serve warm.