Broccoli Gratin with Crispy Onions

10 servings
20 min prep time
45 min total time

This easy broccoli au gratin casserole can be made with fresh or frozen broccoli folded into a simple cultured butter and cheese roux. Crispy fried onions add crunch to this creamy, sublime side dish that can be prepped ahead of any meal.


3 pounds broccoli, cut into florets

6 tablespoons Vermont Creamery Unsalted Cultured Butter - 82% Butterfat divided

1/2 yellow onion, chopped

2 cloves garlic, minced or pressed

3 tablespoons all-purpose flour

2 cups cold whole milk

6 ounces Parmesan cheese, grated

1 teaspoon Kosher salt

1/2 cup crispy fried onions


  • STEP 1

    Preheat oven to 375°F. Butter 2-quart baking dish.

  • STEP 2

    Microwave broccoli and 1/4 cup water 5-7 minutes or until broccoli is tender. (Or cook broccoli and water in steamer basket on stove 12-15 minutes.) Drain.

  • STEP 3

    Meanwhile, melt 1 tablespoon butter in nonstick skillet over medium heat. Add onion and garlic; cook 3-4 minutes or until onion is softened and garlic is fragrant. Stir remaining 5 tablespoons butter into skillet until melted. Sprinkle flour over onion mixture. Cook, stirring, 2 minutes. Slowly whisk in milk. Cook, stirring occasionally, 7-8 minutes or until sauce thickens. Stir in Parmesan cheese and salt.

  • STEP 4

    Fold hot broccoli into bubbly cheese sauce, tossing to coat. Transfer to prepared baking dish; sprinkle evenly with fried onions. Bake 15 minutes or until sauce is bubbly and crispy onions are golden. Serve warm.