Ingredient

• 3 cups (about 12 3/4 ounces) plus 2 tablespoons all-purpose flour, plus more for dusting
• 1 teaspoon instant yeast
• 1 ¼ cups water, at room temperature
• ¼ cup extra-virgin olive oil, divided, plus more as needed
• 2 teaspoons kosher salt
• 3 medium-size (8 ounces) red plums (unpeeled), pitted and cut into 1/2-inch-thick wedges (about 2 cups)
• 3 tablespoons fresh rosemary leaves
• 1 tablespoon plus 1 teaspoon turbinado sugar
• 1 teaspoon flaky sea salt

Direction

1. Stir together flour and yeast in a large bowl until combined. Add 11/4 cups water and 1 tablespoon oil to flour mixture; gently stir with your hands until a shaggy dough forms. Cover bowl with a kitchen towel, and let rest at room temperature 20 minutes to allow flour to hydrate. Transfer dough to a lightly floured work surface. Sprinkle dough with kosher salt, and gently rub salt into dough. Knead dough by pressing the heel of your hand into the dough and dragging it back, repeating this motion until the dough feels smooth to the touch, about 5 minutes. Transfer dough to a lightly oiled bowl; cover with plastic wrap, and let rise at room temperature until doubled in size, about 2 hours.
2. Brush a 13- x 18-inch rimmed baking sheet with 1 tablespoon oil. Transfer dough to a lightly floured work surface. Cut dough in half; tuck cut edges under, and pat each dough half into a 9- x 7-inch oval. Transfer dough ovals to prepared baking sheet spaced at least 1 inch apart. Cover dough with a towel; let rest in a warm (about 80°F) area for 30 minutes. (The top of the dough may get a little dry, but that's OK.)
3. Uncover dough. Using your fingers, press down deeply into dough to form dimples spaced about 1/2 inch apart. Cover dough with a towel, and let rise in a warm area for 30 minutes. Place a pizza stone on middle oven rack, and preheat oven to 450°F.
4. Uncover dough, and lightly press plum slices evenly into dough ovals. Brush dough ovals evenly with remaining 2 tablespoons oil; sprinkle evenly with rosemary, sugar, and flaky salt. Place baking sheet on hot pizza stone in preheated oven, and bake until plum juices have started to caramelize and edges of focaccia are golden brown, 25 to 30 minutes. Remove baking sheet from oven. Let focaccia cool on baking sheet about 15 minutes. Serve warm or at room temperature.