Preheat your broiler to medium heat if the option is available. This will allow the dish to achieve a golden, bubbling cheese topping.

In a large oven-safe skillet, cook the chopped bacon over medium heat until it becomes crispy. Use a slotted spoon to transfer the bacon to a plate lined with paper towels, allowing it to drain.

Drain most of the bacon fat from the skillet, leaving approximately 1–2 tablespoons for flavor. Add the butter to the skillet and allow it to melt. Incorporate the diced onion, cooking until it becomes translucent (about 2 minutes). Add the broccoli florets, season with salt and pepper, and sauté for approximately 3 minutes, stirring occasionally, until the broccoli is bright green.

Stir in the minced garlic, allowing it to become fragrant (approximately 30 seconds). Pour in the cream, reduce the heat to low, and let the mixture simmer for 3–4 minutes, stirring occasionally, until the sauce begins to thicken. If the sauce is too thin, incorporate the cornstarch slurry, mixing well until the desired consistency is achieved.

Return the cooked bacon to the skillet, mixing it thoroughly with the broccoli and cream sauce. Evenly sprinkle the mozzarella and parmesan cheeses over the top of the dish.

Place the skillet under the broiler for 2–3 minutes, or until the cheese is golden and bubbling. Be vigilant during this step to prevent over-browning.

Remove the skillet from the broiler and season with additional black pepper, if desired. Garnish with fresh parsley, thyme, or rosemary for added flavor and presentation. Serve immediately.