Step 1

Preheat the oven to 375°F (190°C).

Step 2

Place the broccoli florets in a medium-sized pot of boiling water and cook for 2 minutes or just until tender-crisp. Drain well and set aside.

Step 3

Melt 1 tablespoon of butter in a 10-inch skillet over medium heat. Add the onions and cook until translucent, about 2 minutes.

Step 4

Add the garlic and cook, stirring frequently for 30 seconds.

Step 5

Pour in the chicken broth, increase the heat to medium-high, stir, and bring to a simmer.

Step 6

Add the heavy cream and bring the mixture back up to a simmer, stirring frequently. Continue to simmer and stir for an additional 2 to 3 minutes to thicken the sauce slightly.

Step 7

Remove the pan from the heat and stir in the sour cream. Next, stir in the Monterey Jack cheese and gently fold in the broccoli.

Step 8

Transfer the broccoli and sauce to a lightly buttered 5x5 inch baking dish and place the dish on a rimmed baking sheet to catch any possible spills.

Step 9

Melt the remaining ½ tablespoon of butter and pour into a medium-sized bowl. Stir in the breadcrumbs and shredded Cheddar cheese.

Step 10

Sprinkle the breadcrumb topping evenly over the casserole and bake uncovered for 20 to 25 minutes or until the casserole is bubbly and the topping is golden.

Step 11

Remove the casserole from the oven and let it rest for 5 to 10 minutes. As the casserole rests, the sauce thickens even more.