Cook the Sausage: In a large skillet, cook the bulk pork sausage over medium heat until browned and fully cooked, breaking it up into crumbles. Drain any excess fat and set aside.
Sauté the Vegetables: In the same skillet, add the finely chopped onion and green bell pepper (if using). Sauté for about 5 minutes, or until the vegetables are softened. Remove from heat and let cool slightly.
Preheat Oven: Preheat your oven to 350°F (175°C). Grease a 9-inch pie dish or a similar baking dish.
Layer Ingredients: In the greased pie dish, evenly spread the cooked sausage. Top with the sautéed onions and bell pepper, followed by the shredded Monterey Jack and cheddar cheeses.
Mix Egg Custard: In a medium mixing bowl, whisk together the eggs, half-and-half, all-purpose flour, baking powder, salt, and black pepper until smooth and well combined.
Pour Egg Mixture: Carefully pour the egg mixture over the sausage and cheese in the pie dish, ensuring it is evenly distributed.
Bake: Place the pie dish in the preheated oven and bake for 35-40 minutes, or until the pie is set and the top is golden brown. A knife inserted into the center should come out clean.
Cool Slightly: Remove the pie from the oven and let it cool for about 5 minutes before slicing.
Garnish and Serve: Garnish the Monterey Sausage Pie with chopped green onions or chives if desired. Serve warm