Follow these simple steps to create The Best French Onion Broccoli Cheese Casserole:

1. Preheat Your Oven: Begin by preheating your oven to 350°F (175°C).
2. Prepare Broccoli: In a medium pot, bring water to a boil. Add the broccoli florets and blanch for 2-3 minutes until bright green. Drain and set aside.
3. Sauté Onions: In a skillet, heat olive oil over medium heat. Add the sliced onions and sauté for 8-10 minutes until golden brown and caramelized.
4. Mix Casserole Ingredients: In a large mixing bowl, combine the condensed French onion soup, sour cream, garlic powder, salt, pepper, and thyme. Stir until well mixed.
5. Combine in a Casserole Dish: Add the blanched broccoli and sautéed onions to the soup mixture. Fold in 1½ cups of the shredded cheese, reserving the remaining ½ cup for topping.
6. Transfer to Baking Dish: Pour the mixture into a greased 9×13-inch casserole dish, spreading it evenly.
7. Add Breadcrumbs: Sprinkle the breadcrumbs evenly on top of the casserole.
8. Top with Cheese: Add the reserved shredded cheese on top of the breadcrumbs.
9. Bake: Place the casserole in the preheated oven and bake for 30-35 minutes, or until the top is golden brown and bubbly.
10. Cool and Serve: Once baked, remove the casserole from the oven and allow it to cool for a few minutes before serving.

These steps will guide you in creating a delicious casserole that everyone will love!