Katie Lee Broccoli Casserole Recipe: Cheesy Bake with Crunchy Topping

This cheesy broccoli bake transforms a humble vegetable into a crowd-pleasing side dish. The combination of tender florets, creamy cheese sauce, and a buttery breadcrumb topping creates layers of texture and flavor that stand out at any meal.

I developed this method to ensure the topping stays crunchy while the center remains rich and gooey. The key is baking it uncovered for the final minutes, which allows the breadcrumbs to turn golden and crisp without drying out the casserole beneath.

What results is a dish that’s both comforting and satisfying, with every bite offering a balance of soft broccoli, velvety cheese, and that irresistible crunch on top. It’s the kind of recipe that turns skeptics into fans.

Serve it alongside roasted meats or as part of a holiday spread. Here’s how to make it perfectly every time.

Ingredients for Katie Lee Broccoli Casserole

Transform simple ingredients into a rich, cheesy bake with irresistible crunch on top.

The cheeses are non-negotiable for optimal texture. Cabot or Tillamook sharp cheddar melts beautifully without separating. Use block cheese and grate it yourself—pre-shredded contains anti-caking agents that create a grainy sauce. For the Parmesan, Parmigiano-Reggiano is worth the splurge. The panko breadcrumbs (found at any Whole Foods or standard grocery) give that signature crispiness the intro promises.

Out of sharp cheddar? Gruyère or Monterey Jack work well. No Dijon? Whole-grain mustard at the same amount adds similar depth. Fresh garlic can replace the powders—use 2 cloves minced. For a gluten-free version, swap the flour for cornstarch (same amount) and use gluten-free panko. The milk can be 2% in a pinch, but whole is ideal (trust me on the full-fat version).

Assemble and refrigerate up to 24 hours before baking. Leftovers keep 4-5 days in the fridge, though the topping softens. Reheat covered with foil at 350°F for 15-20 minutes. Freezes beautifully for 3 months—thaw overnight before reheating.

Step-by-Step Instructions for Broccoli Casserole

Master the technique behind this comforting dish with a velvety sauce and crispy topping.

Step 1: Blanch the Broccoli Florets

Bring a large pot of salted water to a boil. Add the 5 cups Broccoli Florets and cook for 2-3 minutes until bright green and slightly tender but still firm. This blanching step removes the raw edge while preserving texture.

Drain immediately and plunge the florets into ice water to stop the cooking process. Drain again and pat dry with paper towels. I spread them on a clean kitchen towel to remove all excess moisture—this prevents a watery casserole.

Step 2: Prepare the Cheese Sauce

In a saucepan over medium heat, melt 0.25 cup Unsalted Butter. Whisk in the 0.25 cup All-Purpose Flour and cook for 1-2 minutes until bubbly and light golden—this creates a proper roux for thickness.

Gradually whisk in the 1.5 cups Whole Milk until smooth. Cook for 3-4 minutes, stirring constantly, until the sauce thickens enough to coat the back of a spoon. Remove from heat and stir in the 2 cups Sharp Cheddar Cheese, 0.5 cup Parmesan Cheese, 1 tbsp Dijon Mustard, 0.5 tsp Garlic Powder, 0.5 tsp Onion Powder, 0.5 tsp Salt, and 0.25 tsp Black Pepper until melted and smooth.

Step 3: Combine Broccoli and Sauce

In a large bowl, pour the cheese sauce over the blanched Broccoli Florets. Gently fold with a silicone spatula until every floret is evenly coated. The sauce should cling to the broccoli without pooling at the bottom of the bowl.

Transfer the mixture to a greased 9×13-inch baking dish or similar oven-safe dish. Spread it into an even layer, pressing down lightly to remove any air pockets. This ensures even cooking and a consistent texture throughout.

Step 4: Add the Panko Topping and Bake

Melt the remaining 0.25 cup Unsalted Butter and toss with the 1 cup Panko Breadcrumbs and 0.25 tsp Dried Thyme until the crumbs are evenly moistened. Sprinkle this mixture evenly over the broccoli and sauce.

Bake at 375°F for 20-25 minutes until the topping is golden brown and the edges are bubbling. For extra crispiness, broil for 1-2 minutes at the end, watching closely to prevent burning. Let rest for 5 minutes before serving to allow the sauce to set slightly.

Essential Equipment for This Recipe

Mixing Bowls

A good large mixing bowl is essential for tossing the broccoli with sauce. I love my Pyrex glass bowl—it’s sturdy, microwave-safe, and won’t stain from tomato-based sauces. A 3-quart size gives plenty of room for folding without spills.

Saucepan Choice

For the cheese sauce, use a heavy-bottomed saucepan to prevent scorching. My go-to is a 2-quart All-Clad—it conducts heat evenly and has a pour spout for easy transfer. Avoid non-stick for this recipe, as the roux needs to brown slightly.

Baking Dish

A 9×13-inch baking dish is ideal for this casserole. I prefer stoneware for even heat distribution—Le Creuset is my favorite. If using glass, reduce oven temp by 25°F to prevent over-browning. 🔥

Whisk and Spatula

A balloon whisk is perfect for making the roux and sauce smooth. For folding the sauce into broccoli, a silicone spatula won’t scratch your bowls and ensures every floret gets coated. I keep both in my utensil crock for easy access.

Cheese Grater

Freshly grated cheese melts better than pre-shredded. I use a box grater with multiple sides—Microplane makes great ones. The large holes work best for cheddar, while the fine side is perfect for Parmesan.

Cool Tools

For the crispy topping, a pastry brush helps distribute melted butter evenly over panko. I also use a spring-loaded ice cream scoop to portion the casserole neatly onto plates. These small tools make a big difference.

Frequently Asked Questions