Broccoli and Cauliflower Gratin

Preheat the oven to 375 degrees F (190 degrees C). Grease a 9x13 inch baking dish with 2 teaspoons of butter. (Prep time: 5 minutes)

Bring a large stockpot of salted water to a boil. Add the cauliflower florets and cook until tender-crisp, about 8-10 minutes. Transfer to a strainer using a slotted spoon and rinse under cold water to stop the cooking process. (Cook time: 10 minutes)

Add the broccoli stalks to the boiling water and cook for 3 minutes. Add the broccoli florets and cook until the stalks and florets are tender-crisp, about 5 minutes more. Transfer to the strainer and rinse under cold water. (Cook time: 8 minutes)

Thoroughly dry the cauliflower and broccoli with paper towels. Arrange the vegetables evenly in the prepared baking dish. (Prep time: 5 minutes)

In a saucepan, melt 1/2 cup (1 stick) of butter over medium heat. Whisk in the flour and cook, whisking constantly, until the mixture forms a smooth paste (a roux) and begins to lightly brown, about 4 minutes. (Cook time: 4 minutes)

Gradually add the milk, whisking constantly to prevent lumps. Bring the mixture to a simmer, whisking constantly, until the sauce thickens, about 2-4 minutes more. (Cook time: 4 minutes)

Remove the saucepan from the heat. Whisk in the mustard powder, Worcestershire sauce, and black pepper. Stir in the grated Cheddar cheese until it is melted and fully incorporated into the sauce. (Prep time: 3 minutes)

Pour the cheese sauce evenly over the cauliflower and broccoli in the baking dish. Gently tap the dish on the counter a few times to release any trapped air bubbles. (Prep time: 2 minutes)

In a small bowl, combine the Italian seasoned bread crumbs and olive oil. Sprinkle the breadcrumb mixture evenly over the vegetable and cheese sauce. Dust with a pinch of paprika. (Prep time: 5 minutes)

Bake in the preheated oven until the gratin is bubbly and the breadcrumb topping is golden brown, about 30 minutes. Let stand for 5-10 minutes before serving. (Bake time: 30 minutes)