A creamy lemon-and-herb spread—made from protein- and calcium-rich ricotta and Greek-style yogurt—is the ideal base for earthy, mustardy root vegetables. Thinly sliced prosciutto brings extra richness and flavor.
Let pizza dough stand at room temperature for 30 minutes. Place a large baking sheet, upside down, on lowest oven rack. Preheat oven to 475°F.
Meanwhile, stir together ricotta, yogurt, mozzarella, herbs, garlic, and lemon zest in a medium bowl. Using a mandoline, thinly slice turnip and rutabaga to yield 1/2 cup of each.
Stretch dough into a 15x11-inch rectangle or oval on a large sheet of parchment paper. Brush with 1 tablespoon oil. Spread ricotta mixture evenly over dough, leaving a 3/4-inch border. Shingle rutabaga and turnip slices evenly over ricotta mixture.
Carefully transfer parchment with dough to upside-down baking sheet. Bake until golden brown around edges and bottom is crisp, about 20 minutes, topping evenly with prosciutto during final 4 minutes of cooking. Drizzle with remaining tablespoon oil, and garnish with more tender herbs. Cut into 6 squares.