This Make Ahead Breakfast Casserole with Sausage and Veggies makes mornings easy. Cook it the night before, let it sit overnight, then pop it in the oven the next morning - you’ve got a simple and delicious meal that also happens to be gluten free!
Cook the sausage in a non-stick pan over medium heat until no longer pink (5-7 minutes), breaking it up as it cooks with a wooden spoon or spatula
While the sausage is cooking, thinly slice the fennel bulb and onion. Set aside.
Once the sausage is done, remove with a slotted spoon on a paper towel lined plate to drain, leaving the grease in the pan.
Place the thinly sliced fennel and onion into the greased pan, along with ½ teaspoon kosher salt and cook until both are turning translucent and starting to brown, about 15-20 minutes. Be sure to stir every couple of minutes so the veggies don’t burn.
While the fennel and onion are cooking, crack eggs into a large bowl. Pour in the milk, ½ teaspoon of kosher salt, and ground black pepper. Whisk together until fully combined. Also grease a 9x13 baking dish and set aside.
Once the fennel and onion are done cooking, place the baby spinach in the pan and cook until wilted, about 3-4 minutes
Place the cooked sausage in an even layer in the baking dish, then place the veggies over the sausage in an even layer. Next pour the egg mixture over everything, making sure most of the veggies are covered (it’s okay if some parts are above the egg).
Put saran wrap over the top of the dish and put it in the fridge overnight. Alternatively, you can also cook it right after making it, if you wish (just skip step 9).
In the morning, take the baking dish out of the fridge and let come up to room temperature (about 30 minutes).
Preheat the oven to 350°F, then bake the dish in the oven for 35-40 minutes. Insert a toothpick in the middle to make sure it’s cooked through. Let sit for 5 minutes to cool slightly before serving!