Broccoli Cheese Casserole is one of the best side dishes ever created. It's a comforting casserole made with broccoli, cheese sauce, and buttery Panko topping.
Preheat the oven to 375° Lightly grease a 9x9 casserole dish (or 9x13 casserole dish)
In a large pot, bring water to boil and blanch broccoli florets for about 2-3 minutes. Drain well and set aside.
In a large pot, melt butter over medium heat and add diced onion. Cook until onion is transparent. Add pressed garlic and saute just until garlic is fragrant.
Sprinkle flour over onions, stir, and cook until paste is formed. SLOWLY, start pouring in milk, whisking constantly. Keep slowly whisking until sauce thickens.
Stir in Dijon mustard, salt, and pepper.
Gradually add your cheeses, while stirring slowly, until all melted and smooth.
Take off heat and stir in broccoli florets. Mix it well and transfer into the casserole dish.
In a small bowl, combine Panko and grated Parmesan. Mix and pour melted butter over it. Mix well and sprinkle the mixture evenly over the casserole.