Cook Bacon:
In a large skillet over medium heat, cook bacon until crisp. Remove and drain on paper towels. Once cooled, crumble bacon into pieces.

Preheat Oven:
Preheat oven to 375°F (190°C). Grease a 9×9-inch baking dish.

Mix Eggs:
In a bowl, whisk together eggs, heavy cream, salt, and pepper until well combined.

Assemble:
Spread cooked onions and bell peppers evenly in the baking dish. Sprinkle crumbled bacon on top. Pour egg mixture over everything. Top with shredded Swiss cheese.

Bake:
Bake for 25–30 minutes, or until eggs are set and cheese is melted and golden.

Serve:
Sprinkle with chopped fresh chives if desired. Serve warm.