Preheat the oven to 350 degrees F. If using, place a pizza stone in the oven.
Cut the squash in half lengthwise. Hold one half on its end, and with a sharp knife, shave the tough peel. Remove the seeds and pith. Set the squash flat side down and cut into 1/4 inch thick slices. Repeat with the other half, or until you have 2 cups sliced squash.
Spread the squash out on an oiled baking sheet. Brush it liberally with 2 tablespoons of the olive oil, and sprinkle with salt and pepper to taste. Bake for about 20 minutes, or until soft. It is okay if the squash is slightly underdone since it will continue to cook on top of the pizza.
Remove from the oven and increase the oven temperature to 500 degrees F.
In a small saute pan, heat the remaining 2 tablespoons olive oil over medium-high heat. Once the oil begins to darken, remove the pan from the stove and toss in the garlic, swirling it around to caramelize it. Set aside.
In another small saute pan, heat the butter over high heat. When it begins to bubble, add the sage leaves and cook for 30 seconds. Watch carefully, the leaves can easily burn. Remove from the butter and drain on a paper towel.
Dust the pizza pan with cornmeal. Stretch the dough out on the pan, using your fingers to stretch it from the center toward the edges. (Since the dough is very loose and pliable, this takes a little patience.) The middle of the dough will be paper-thin. Brush it liberally with the garlic oil. Sprinkle the Gruyere cheese over the dough. Arrange the squash slices in concentric circles over the cheese, spacing them about 1 inch apart. Bake for 15 mintues. Remove from the oven and top with blue cheese and sage leaves, placing the leaves decoratively on the pizza. Continue baking until the cheese is bubbling and the edges of the crust have browned, 5 to 10 minutes more. Remove from the oven and serve immediately.
Dissolve the yeast in the warm water. Let it sit for about 10 minutes, until it becomes foamy.
In a large bowl, mix together the oil and the salt. Add the yeast mixture and stir well. Slowly add 3 cups of the flour and mix until the dough sticks together but isn't too dry. Turn the dough onto a floured surface and knead in the remaining 1/2 cup flour, or as much as you need until the dough becomes smooth and elastic. (For a thinner crust, use slightly less flour. The dough will be a little stickier, however.)
Form the dough into a ball and place it in an oiled bowl, turning once to coat the dough with oil. Cover with plastic wrap or a towel and set in a warm place. Let rise until doubled in bulk, 1 1/2 to 2 1/2 hours.
Divide the dough into two balls. Let rest, covered, for 15 minutes. Proceed according to individual recipe.