Focaccia with Grapes (Schiacciata con L'uva)

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 400F.

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.