Heat oil in a skillet; add sage and cook until oil has absorbed the scent. Remove sprigs and cool.
In a standing mixer, add 1 C lukewarm water to the mixing bowl. Add yeast and let sit until foamy (3-5 minutes). Add oil, flour, cornmeal, 1/4 cup sugar, and 1 teaspoon salt. Mix until dough comes together. Knead dough in mixer for 5-10 minutes, adding flour if dough is too sticky.
Remove dough from mixer and hand knead until elastic, another 5 minutes.
Preheat oven to 375 degrees F. Allow dough to rise for 1 hour (or until doubled in size) in a greased bowl.
Spread dough on an oiled baking sheet, stretching, but not ripping. Push grapes and pine nuts into the dough. Sprinkle with remaining 2 tablespoons of sugar and 1 teaspoon sea salt. Drizzle all with remaining 2 tablespoons oil and bake 30 minutes or until browned.