11×7-inch Baking Dish
- 8 cups broccoli florets (from 2 to 3 crowns)
- 3 ½ Tbsp. extra-virgin olive oil, divided
- 2 large leeks, white and pale green parts only, halved lengthwise, thinly sliced into half moons (about 1 cup total)
- 1 cup chopped shallots (sub yellow onion)
- 3 minced garlic cloves
- ⅓ cup dry white wine (sub 5 Tbsp. vegetable or chicken broth mixed with 1 Tbsp. sherry vinegar)
- 2 Tbsp. all-purpose flour
- 1 ¾ cups whole milk (sub unsweetened plain cashewmilk)
- ½ tsp. each kosher salt and black pepper
- 1 cup freshly grated sharp white cheddar cheese
- ¾ cup panko breadcrumbs
Steam the broccoli one of two ways:
Option 1- In the Microwave: Combine broccoli and ¼ cup water in a large microwavable glass bowl; cover loosely with plastic wrap. Microwave until crisp-tender, about 5 minutes. Drain and set aside.
Option 2- Stovetop: Place broccoli florets in a steamer basket. Add enough water to a pot to come up to about 1 inch, and bring to a boil over medium-high heat. Once boiling, place the steamer basket with broccoli into the pot. Steam for 5 minutes.
Preheat oven to 425ºF and grease an 11×7-inch baking pan.
Heat 2 Tbsp. of oil in a large skillet over medium-high. Once hot, add the leeks and shallots; cook until softened, about 8 to 10 minutes. Add the garlic; cook 1 to 2 minutes, until aromatic.
Add the white wine (or both + vinegar mixture) to the pan. Cook 2 to 3 minutes, stirring often, until the liquid is mostly evaporated.
Sprinkle flour into pan and cook, stirring constantly, for 1 to 2 minutes, until onion pieces are coated. Whisk in milk, and bring to a simmer. Cook, whisking occasionally, until the mixture starts to thicken, about 4 to 5 minutes. Stir in salt and pepper.
Stir in cheese and continue cooking, stirring constantly, until the cheese melts and sauce is smooth, about 1 minute. Remove from heat and stir in broccoli florets. Transfer mixture to prepared baking pan.
Combine panko breadcrumbs and remaining 1 ½ Tbsp. olive oil in a small bowl. Use your hands to stir the mixture, making sure all breadcrumbs are well-coated. Scatter panko over broccoli cheese casserole, and transfer to the oven. Bake, uncovered, for 20 minutes, until the panko is golden and casserole is bubbly.
NotesMake Ahead Options: Steam broccoli up to 2 days ahead and keep refrigerated in an airtight storage container. Prep casserole 4 to 6 hours in advance, however wait to add panko until right before baking.
To Store: Store leftovers in an airtight storage container in the refrigerator for up to 4 days.
To Reheat. Reheat individual portions in the microwave, or reheat entire casserole in an oven-safe pan at 350ºF. If using the oven, loosely tent the pan with foil and place the pan on the center rack for 15 to 25 minutes, until warmed through (the larger the serving, the longer you will need). Add a splash of broth to rehydrate the cream sauce before reheating, if necessary.
To Freeze. Place leftovers in an airtight freezer-safe storage container in the freezer for up to 3 months. Let thaw overnight in the refrigerator before reheating.
NutritionServing: 0.75cup | Calories: 205kcal | Carbohydrates: 16.5g | Protein: 8.5g | Fat: 13g | Saturated Fat: 2g | Sodium: 370mg | Fiber: 3g | Sugar: 6g