Proof yeast in sugar and lukewarm water for 5 minutes until foamy.

In a large bowl, combine flour, salt, and 3 tablespoons of olive oil.

Mix the ingredients to form a dough.

Knead the dough for 2 minutes.

Shape the dough into a ball.

Transfer the dough to an oiled bowl, turning to coat.

Cover the bowl with plastic wrap and let rise in a warm place for 1 1/2 hours, or until doubled in size.

Press the dough into a 15 1/2 X 10 1/2 inch oiled jelly-roll pan.

Cover loosely and let rise in a warm place for 1 more hour.

Preheat oven to 400 degrees F and place rack in the bottom third.

In a large bowl, stir together the remaining 3 tablespoons of olive oil, sliced yellow onion, sliced red onion, sliced shallot, chopped scallions, crumbled dried sage, pepper to taste.

Spread the onion mixture evenly over the dough.

Sprinkle with grated Parmesan cheese and coarse salt.

Bake in the bottom third of the oven for 35-45 minutes, or until golden-brown.