Smoked-Salmon Flatbread with Pickled Beet

Preheat oven to 450°F, with a pizza stone or inverted baking sheet on lowest rack. Drizzle 3 tablespoons oil onto a rimmed quarter sheet pan (9 by 13 inches). Stretch dough to edges of pan.

Drizzle dough evenly with remaining 1 tablespoon oil; sprinkle with sesame seeds and season with salt and pepper. Top with mozzarella and garlic-herb cheese, leaving a 1/2-inch border.

Bake on stone until cheese is melted and bubbly, and crust is golden brown and set on bottom, 22 to 24 minutes. Meanwhile, in a bowl, combine beet, lemon zest and juice, and 3/4 teaspoon salt. Let stand 10 minutes. Remove pizza from oven; let cool slightly. Top with salmon, beet mixture, and herbs. Slice and serve.