Cook the chorizo, onion and bell pepper: Get out a large skillet and place it on your stove over high heat. Once the pan is hot toss in the chorizo and cook it until it begins to brown. Make sure to break up the chorizo as it is cooking as we don’t want any large chunks. Once the chorizo is cooked take it out of the pan and transfer it to a large bowl. Place the pan back on the heat, toss in the onion and pepper and saute for 5 minutes. Once the onion and bell pepper are cooked take them out of the pan and transfer them to the same bowl you have the chorizo in. let these ingredients cool off completely before moving on to the next step.
Make the casserole filling: Once the chorizo, onion, and bell pepper have cooled off toss in the jalapeno, hashbrowns, and cheese. Then use a spoon to mix all of those ingredients together.
Make the egg mixture: Get out another large bowl and crack all 12 eggs into it. Then whisk the eggs together. Finally, add in the milk and salt mixing everything together.
Make the casserole: Get out a 9 x 13 baking dish and grease it with some spray oil. Then toss in the casserole filling making sure that it is distributed evenly in the baking dish. Then pour in the egg mixture and use a spoon to poke the casserole so that the egg mixture seeps into every nook and cranny.
Let the casserole rest overnight in your fridge.
Preheat your oven to 325 degrees Fahrenheit.
Bake the casserole: Once the oven is hot toss in the casserole and let it bake for 1 to 1 ½ hours. Check on the casserole after 45 minutes and if the top of the casserole is getting too browned up then cover the baking dish with some aluminum foil. You will know that it is completely cooked through when you stick a toothpick in the middle and it comes out clean.
Let the casserole sit for 10 minutes before slicing up into pieces. Garnish each piece with some minced cilantro and a dollop of salsa.