- 1 package active dry yeast (2 1/2 teaspoons)
- 3 tablespoons Chianti or other dry red wine
- 1 tablespoon honey
- 3/4 cup warm water (110–115°F)
- 2 1/2 to 3 cups Italian “00” flour or half all-purpose flour and half cake flour (not self-rising)
- 1/4 cup fine-quality extra-virgin olive oil (preferably Tuscan)
- 1/2 teaspoon fine sea salt
- 3 1/2 cups Concord or wine grapes (1 1/2 pounds)
- 1/2 cup sugar
- Stir together yeast, wine, honey, and warm water in a large bowl until yeast is dissolved. Let stand until bubbly, about 10 minutes.
- Stir in 1 cup flour (mixture will be lumpy). Cover bowl with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, 40 to 50 minutes.
- Add oil, 1 1/2 cups flour, and sea salt and stir until a sticky dough forms.
- Knead dough on a floured work surface, gradually adding up to 1/2 cup more flour if necessary to keep dough from sticking, until dough is smooth and elastic but still soft, 8 to 10 minutes.
- Transfer dough to an oiled large bowl and turn to coat. Cover bowl with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, about 1 hour.
- Turn out dough onto work surface and knead several times to release air. Cut dough in half. Roll out 1 piece of dough, keeping remaining piece covered, with a lightly floured rolling pin into a rough 12- by 10-inch rectangle. Transfer dough to a lightly oiled 15- by 10- by 1-inch baking pan and gently stretch to cover as much as possible of bottom (dough may not fit exactly).
- Scatter half of grapes over dough, then sprinkle grapes with 1/4 cup sugar. Roll out remaining piece of dough in same manner and put on top of grapes, gently stretching dough to cover grapes. Scatter remaining grapes and 1/4 cup sugar on top and gently press into dough. Cover pan with plastic wrap and a kitchen towel and let rise in a warm place until doubled in bulk, about 1 hour.
- Preheat oven to 400°F.
- Bake schiacciata in middle of oven until well browned and firm in middle, 40 to 45 minutes. Loosen sides and bottom of schiacciata with a spatula and slide onto a rack to cool. Serve at room temperature.