1. Preheat oven to 500F, with a rack in the center.

2. Use a mandoline or chef's knife to cut the onions into thin slices (1/8 inch thick); you want about 6 cups sliced onion. In a medium bowl, toss together the onion slices, heavy cream, salt and thyme.

3. Spread the onion mixture evenly over the dough going all the way to the edges; put a bit more topping around the edge of the 'pie', as the outside tends to cook more quickly.

4. Bake for 30-35 minutes, until the topping is starting to turn golden brown and the crust is pulling away from the sides of the pan. Serve the pizza hot or at room temperature.

1. In a medium bowl, stir together the flour, yeast, salt and sugar. Add the water and using a wood spoon or your hand, mix until blended, at least 30 seconds. The dough is a bit stiff, not wet and sticky. Cover the bowl and let sit at room temperature until the dough has more than doubled in volume, about 2 hours.

2. Oil rimmed baking sheets or pans you'll be using. Use a bowl scraper or rubber spatula to scrape 1/2 the dough onto an oiled pan in one piece. Gently pull and stretch the dough across the surface of the pan and use your hands to press it evenly out to the edges. If the dough sticks to your fingers, lightly dust it with flour or coat your hands with oil. Pinch any holes together. Repeat witht he second piece. The dough is ready to top as your like.