Step 1

Place oven rack in middle position, and place a pizza stone on rack. Preheat oven to 450 degrees. Combine yeast, sugar, and water in the bowl of a standing mixer fitted with the dough hook attachment. Let stand until foamy, about 10 minutes. Stir until yeast and sugar have dissolved. Add 6 tablespoons oil, the chopped rosemary, flour, coarse salt, and Parmesan, and beat on medium speed until dough forms a ball, about 2 minutes.

Step 2

On a lightly floured surface, knead dough until smooth and elastic. Lightly brush a medium bowl with oil. Place dough in bowl. Cover with a clean kitchen towel, and let rise in a warm place until doubled in size, about 1 hour.

Step 3

Punch down dough, and turn out onto a lightly floured surface. Cut in half, cover, and let rest for 10 minutes.

Step 4

On a lightly floured piece of parchment, roll 1 portion of dough into a 9-by-16-inch rectangle, about 1/4 inch thick. Brush with 2 tablespoons oil. Arrange half the Taleggio on top, and sprinkle with 1 teaspoon whole rosemary leaves. Slide parchment and dough onto an inverted baking sheet, and use the sheet to slide parchment and dough onto the preheated stone in oven.

Step 5

Bake, rotating bread once, until crust is just golden and cheese is bubbling, 10 to 12 minutes. Transfer parchment and bread to a wire rack. Shave half the truffle over top if desired, and sprinkle with flaked sea salt. Repeat with remaining dough, 2 tablespoons oil, 1 teaspoon rosemary leaves, and Taleggio. Slice into wedges or squares, and serve warm or at room temperature.