Make the pumpkin sauce mixture. Sauté one diced sweet onion and 1 teaspoon sugar in a saucepan. Add it to a mixing bowl with 1 can pumpkin puree, ¼ teaspoon ground nutmeg, 1 diced shallot, ½ cup Parmesan cheese, 2 teaspoons thyme and salt and pepper. Mix until smooth, then spread the pumpkin mixture onto the pizza dough.