Begin by preheating your oven to 180°C (350°F). Chop the broccoli into bite-sized pieces, then blanch in boiling water for about 2 minutes until bright green and slightly tender. Drain well and set aside.
In a saucepan, melt 2 tablespoons of butter over medium heat. Add the diced onion and sauté for about 3-4 minutes until fragrant and translucent, filling the kitchen with a sweet aroma.
Stir in the can of cream of mushroom soup and milk, whisking until the mixture is smooth and heated through, about 2 minutes. This creates a rich, earthy sauce that will coat the broccoli beautifully.
Gradually add the grated cheddar cheese into the warm sauce, whisking continuously until melted and creamy. Season with salt and pepper, tasting and adjusting as needed for flavor balance.
In a large mixing bowl, combine the blanched broccoli with the cheese sauce, gently folding until all pieces are evenly coated with the cheesy goodness.
Prepare the breadcrumb topping by mixing panko breadcrumbs with melted butter, paprika, and a pinch of salt in a small bowl. Toss until evenly coated, creating a flavorful, crispy topping.
Transfer the broccoli and cheese mixture into your prepared baking dish, spreading it out evenly to ensure uniform baking and crispy edges.
Sprinkle the buttery breadcrumbs evenly over the top, covering the casserole fully for a crispy, golden crust.
Bake uncovered in the preheated oven for 25-30 minutes, until the top turns golden brown and crispy, and the filling is bubbling around the edges.
Once out of the oven, let the casserole rest for about 5 minutes. This helps it set, making it easier to serve clean slices topped with crispy crumbs and cheesy goodness.
Serve hot, perhaps with a simple side salad, and enjoy the comforting, cheesy, crispy goodness of this classic broccoli cheese casserole.
