Preheat your oven to 350°F (175°C). Grease a 9 x 13-inch pan.

In a large mixing bowl, combine the extra lean ground beef, Italian sausage, eggs, milk, and 2 cups of crushed Doritos. Mix until well incorporated.

Press half of the meat mixture into the greased baking dish, forming an even layer.

In a separate bowl, blend together the softened cream cheese, ranch dressing mix, and 1 tablespoon of milk until smooth. Spread over the meat layer.

Layer the diced green bell pepper evenly over the cream cheese mixture, followed by half of the shredded mozzarella cheese.

Spread the remaining meat mixture on top and press down firmly.

Bake for 40 minutes until the meat is cooked through and the edges are bubbly.

Remove from oven, sprinkle remaining mozzarella cheese and crushed Doritos on top, and bake for an additional 10 minutes.

Let the casserole rest for 10 minutes before cutting into squares and serving.