Dissolve Yeast: Begin by dissolving the yeast in half of the water.
2 ¼ tsp active dry yeast, ¾ cup + 2 tbsp water
Prepare Dough: Place flour in a mixer's bowl, add yeast and oil. Mix at low speed, gradually adding water until the dough is neither too soft nor too hard. Switch to a dough hook and knead for 15 minutes to get a smooth, elastic dough. Let it rise in a bowl, covered with plastic wrap, until doubled in size, about 2 hours.
3 ¼ cups all-purpose flour, 4 tbsp olive oil
Shape Base: Take two-thirds of the risen dough and spread it by hand onto a 9x9 inch baking sheet lined with parchment and oiled. Cover the base and partly up the sides.
Add Grapes: Scatter the grapes from one bunch over the dough, sprinkle with 3 tbsp sugar, and drizzle with oil.
6 tbsp granulated sugar, 2 bunches of black grapes
Cover with Dough: Roll out the remaining dough and cover the grape layer. Seal the edges with your fingers.
Top with more grapes: Spread the remaining grapes over the top and gently press them into the top dough, sprinkle with the rest of the sugar, and a little oil. You can also crush the grapes with your fingers to release the juice if you like to give it a more rustic look.
Bake in oven: Bake in a preheated oven at 375°F for 45-50 minutes until golden. Cool completely before serving.