Start the focaccia the day before. In a large bowl of a stand up mixer, dissolve the yeast in 1/3 cup of water along with 1 Tbsp. of whole wheat flour, allow to bubble for at least 5 minutes. Using the paddle attachment beat in remaining 2 1/3 cups of water, remaining whole wheat flour, 4 1/2 cups white flour and the sea salt. Mix on medium-low for approximately 5 minutes until the dough is soft, sticky, and very elastic. Switch to the dough hook and knead for 10 minutes adding 1/2 to 3/4 cups white flour until the dough cleans the side of the bowl, add a little more flour if needed until it is soft and just a little sticky. Place in a large oiled bowl, cover with plastic wrap and refrigerate for 8 to 12 hours.

Turn the dough out on a lightly floured surface and knead a few times. Return the dough to the bowl and let rise at room temperature for about 4 hours, the dough should almost triple in bulk. Knead the dough with floured hands. Oil an 18 x 13 inch sheet pan and stretch the dough to fill the sheet, the dough should be approx 1/2" thick. Cover with a towel and allow to rise at room temperature for 1 1/2 to 1 3/4 hours.

Preheat the oven to 400F, arrange the tomato slices on the focaccia dough. Top with the chopped onions, herbs and garlic. Drizzle with olive oil and sprinkle with salt and pepper. Bake 40 minutes or until the dough is a rich golden brown, the tomatoes and onions should appear slightly withered.

Using a large spatula, take the bread out of the pan sprinkle with cheese and place back in the oven, directly on the oven rack and bake for another 5 - 10 minutes, until the loaf sounds hollow when tapped on the underside.

Serve warm or at room temperature.