Preheat Oven:

1. Preheat the oven to 400°F (200°C).

Brown Sausage:

1. In a skillet, brown the sausage over medium heat until fully cooked.

Prepare Vegetables:

1. Dice the red pepper, sweet onion, and mushrooms. Add them to the skillet with the browned sausage.

Add Garlic:

1. Add the minced garlic to the skillet and sauté with the sausage and vegetables for a few minutes until fragrant.

Prepare Batter:

1. In a separate bowl, whisk together the milk, eggs, Bisquick, sage, and pepper until smooth.

Combine Cheese:

1. Mix 2 cups of grated Monterey Jack cheese into the meat and vegetable mixture in the skillet. Reserve about ½ cup of cheese for garnish.

Assemble:

1. Pour the sausage and vegetable mixture into a greased deep-dish pie plate.
2. Pour the batter from the mixing bowl over the top.

Bake:

1. Bake in the preheated oven for 20 to 25 minutes, or until the pie is set.

Garnish:

1. Sprinkle the remaining ½ cup of cheese on top and bake for an additional 1 to 2 minutes, just until the cheese melts.

Cool and Serve:

1. Allow the pie to cool for a few minutes before slicing and serving.