If using bacon, cook it according to personal preference, taking care not to make it too crispy, as it will be baked later.
In a large skillet or pan over high heat, sear the steak tips until browned on all sides.
Transfer the steak to a plate or bowl and drain off the fat, leaving 1 tablespoon in the skillet.
Reduce the heat to medium-low and add the sliced onions. Season with salt and pepper and sauté for 10-12 minutes, stirring occasionally, or until the onions are softened, translucent, and golden brown.
Add the minced garlic and cook for another 1-2 minutes or until fragrant.
Place the steak tips in a large baking dish, add bacon strips (if using), and cover with caramelized onions and garlic.
Top with both cheeses and sprinkle with herbs de Provence.
Bake in the preheated oven for 15-20 minutes or until the cheese is melted and bubbly, and the steak is cooked through.