Mix the warm water with the yeast and the sugar in a bowl and let sit for around 10 minutes until foamy.
Add in the flour and sea salt.
Mix with an electric mixer using the dough hook, starting on low speed and increasing to medium as the ingredients come together. Mix for about 10 minutes. Dough should be soft, smooth and sticky.
Drizzle the dough with about 1 Tbsp of the olive oil, turn the dough over a few times to make sure it’s all coated. Cover and let rise 1-2 hours until doubled in size.
Pour about 2 Tbsp olive oil into a 9”x13” baking pan and spread it evenly all over the bottom and sides of the pan.
Lightly punch down the dough and dump it into the baking pan, turning it over a couple of times and then spreading it to fill the pan in a rectangle shape.
Let the dough rise again, uncovered, for another hour or so, until it fills the pan.
Oil your hands and make dimples all over the dough.
Pour another 1 Tbsp of oil evenly over the dough.
Evenly distribute the grapes and rosemary leaves over the surface of the dough.
Sprinkle evenly with flaky salt and a good amount of freshly cracked black pepper (I do some finely ground and some coarse).
Bake at 450 degrees for 25-30 minutes until golden brown.