Brown the Sausage: In a large skillet, cook the bulk pork sausage over medium heat until browned and fully cooked, breaking it up into crumbles as it cooks. This should take about 8-10 minutes. Once cooked, drain off any excess fat and set the sausage aside.

Prepare the Vegetables: Using the same skillet, add the finely chopped onion and green bell pepper (if using). Sauté for approximately 5 minutes, or until the vegetables have softened and become translucent. Remove from heat and allow to cool slightly.

Preheat and Prepare: Preheat your oven to 350°F (175°C). While waiting, grease a 9-inch pie dish or similar sized baking dish to prevent sticking.

Layer the Base Ingredients: In the greased pie dish, evenly spread the cooked sausage as the bottom layer. Next, distribute the sautéed onions and bell peppers over the sausage. Sprinkle the shredded Monterey Jack and cheddar cheeses evenly over the vegetables.

Create the Custard Mixture: 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. This creates the custard that will bind everything together.

Assemble the Pie: Carefully pour the egg custard mixture over the layered ingredients in the pie dish, ensuring it is distributed evenly and reaches all corners of the dish.

Bake to Perfection: Place the assembled pie dish in the preheated oven and bake for 35-40 minutes. The pie is done when it becomes set in the center and the top turns a beautiful golden brown color. To test, insert a knife into the center - it should come out clean.

Rest Before Serving: Remove the pie from the oven and allow it to cool for about 5 minutes. This resting period helps the pie set and makes it easier to slice.

Garnish and Serve: Just before serving, sprinkle chopped green onions or chives over the top if desired. Slice the pie into wedges and serve while still warm.