Step 1

Arrange a rack in the middle of the oven and heat to 375°F. Generously coat a rimmed baking sheet with cooking spray or oil.

Step 2

Cut the broccoli florets from the stalks. Peel the stalks with a vegetable peeler, then chop the stalks and florets into bite-size pieces. Arrange the broccoli and tomatoes on the baking sheet in a single layer.

Step 3

Roast until the broccoli is tender, 12 to 15 minutes. Meanwhile, whisk the eggs, milk, salt, and pepper together in a large bowl or spouted measuring cup.

Step 4

Carefully pour the eggs onto the baking sheet over the vegetables. Sprinkle with the cheese. Bake until the frittata is puffed around the edges, golden in spots, and a knife inserted in the center comes out clean, 25 to 30 minutes. Cool completely before slicing.