Italian Herb Focaccia with Three Cheese and Caramelized Onions

2 cups water, at 70 degrees F
2 teaspoons RapidRise yeast
4 to 4 1/2 cups bread or all-purpose flour
1 tablespoon sea salt
1/4 cup olive oil, plus additional for coating dough

Place water and dry yeast in a 5 quart Kitchen Aid mixer bowl. Let sit 5 minutes. Scoop in bread flour, and add salt and 1/4 cup olive oil. Mix 6-7 minutes. Dough will be sticky but manageable. Cover dough well with olive oil and a damp cloth. When the dough has risen, take it out of the bowl and place on a 15 inch by 10 inch baking sheet that has been coated with olive oil. Push the dough outward with your hands. Let the dough rest and repeat until the dough totally covers the baking sheet and doesn’t spring back. Let the dough rest on the baking sheet until it reaches double its size. While waiting, gather the following ingredients:
2 onions, sliced and caramelized (see note)
3/4 cup shredded Asiago cheese
3/4 cup shredded sharp Cheddar cheese
3/4 cup shredded Gruyère cheese
2 tablespoons Italian herb seasoning
When dough has doubled in size, use your fingertips to dimple the dough. Spread caramelized onions, cheeses and herb seasoning on top of dough, and push into the dough. Let the dough rise again until it comes up and over all the ingredients on top. Brush olive oil on top, and bake in a 375 degree F oven for 20 to 25 minutes or until golden brown. Let cool. Slice and serve.
NOTE: To caramelize onions, heat 2 tablespoons olive oil in a medium sauté pan over medium heat. Add onions and cook, stirring until onions are translucent. Sprinkle onions with 1 tablespoon sugar, salt and pepper to taste. Continue to cook until onions are very soft and well caramelized.