Preheat your oven to 375°F (190°C). Lightly grease a 9-inch pie dish or tart pan for easy cleanup.

In a skillet over medium heat, cook the breakfast sausage until browned and crumbled. Drain excess grease and set aside. In the same skillet, sauté the diced onion and bell pepper until softened, about 5 minutes. Add the minced garlic and cook for 1 minute, until fragrant. Remove from heat and let cool slightly.

Roll out the puff pastry sheet and gently press it into the prepared pie dish, trimming any excess edges. Sprinkle half of the shredded Monterey Jack cheese evenly over the bottom of the pastry crust. Spread the cooked sausage mixture over the cheese layer. Top with the remaining shredded cheese.

In a mixing bowl, whisk together the eggs, heavy cream, thyme, salt, and black pepper until smooth. Pour the custard mixture evenly over the filling in the pie dish.

Brush the edges of the puff pastry with the beaten egg for a golden finish. Bake in the preheated oven for 35–40 minutes, or until the crust is golden brown and the custard is set in the center. Optional: Broil for the last 2–3 minutes to achieve an extra golden crust (watch closely to avoid burning).

Remove the pie from the oven and let it cool for 5–10 minutes before slicing. Optional: Garnish with fresh thyme or parsley for added color and freshness. Enjoy every bite of this savory, cheesy, and indulgent Monterey Sausage Pie!