Preheat your oven to 375°F (190°C).
Prepare the pie crust in a 9-inch pie dish.
Chop the bacon and cook in a skillet over medium heat until crispy.
Remove bacon and drain on paper towels, then reserve some fat in the skillet.
Add halved Brussels sprouts to the skillet, drizzle with olive oil, salt, and pepper, and roast them for about 20 minutes.
In a mixing bowl, whisk together the eggs and heavy cream, seasoning with salt and pepper.
Stir in the cooked bacon, roasted Brussels sprouts, and cheese into the egg mixture.
Pour the filling into the prepared pie crust.
Bake for 30-35 minutes, or until the filling is set and the top is golden brown.