For the pizza dough

1. Proof yeast. In a small bowl, stir together water, yeast, and sugar until the yeast is dissolved. Let mixture stand at room temperature until foamy, about 3-5 minutes.
2. Mix dough. In a large bowl whisk together 4 1/4 cups flour and salt. Stir in olive oil and yeast mixture with a spatula or wooden spoon (see Note 2). Continue stirring until the dough starts to come together. 
3. Knead dough. Transfer dough to a lightly floured surface and knead for 5 minutes by hand until smooth. Add more flour if the dough gets too sticky but try to add the least amount of flour as possible.
4. Rise. Divide the dough into 3 equal portions. Place each in a covered and lightly oiled quart-sized deli container, zipper freezer bag or  bowl. Place dough containers in the refrigerator and let rise for at least 2 hours and up to 3 days.

For the caramelized onions

1. Sweat onions. Heat olive oil in a medium sauté pan. Add onions and thyme leaves. Cook for 1-2 minutes until onions soften slightly.
2. Season. Add sugar and salt to the onions and stir until dissolved.
3. Caramelize onions. Cook the onions over medium-low heat until all the liquid is evaporated and the onions begin to brown and caramelize, about 20 minutes, stirring occasionally. Continue cooking until the onions are a deep brown, scraping up any fond that forms on the bottom of the skillet with a wooden spoon or spatula. It can take up to 45 minutes until the onions are fully caramelized.
4. Deglaze. Add wine to the pan. Allow the wine to cook off, using a spatula to scrape up any browned bits at bottom of the pan and stir into the onions.

To make the pizzas

1. Prep dough. At least 2 hours before using the dough, remove it from the refrigerator and let it rest at room temperature.
2. Prep oven. Place a pizza stone on a rack in lower third of oven. Heat oven to 500 degrees F for about an hour.
3. Stretch dough. Working with one dough ball at a time place dough on a large piece of parchment paper. Working from center, pat and flatten dough with fingertips until it is about 7 inches in diameter. Let rest for 2-3 minutes. Gently stretch dough from edges to about 8 inches in diameter. Let rest for 2-3 minutes. Continue patting and stretching the dough until it is 9-11 inches in diameter.
4. Add toppings. Top dough with 1/3 of the mozzarella, 1/3 of the blue cheese, 1/3 of the caramelized onions, 1/3 of the prosciutto, and 1/3 of the peach slices.
5. Adjust oven temp. Reduce oven temperature to 475 degrees F.
6. Bake. Transfer pizza (on paper) to stone using a large cookie sheet or pizza peel; bake for 5 minutes then carefully pull out the parchment and finish baking the pizza directly on the stone (see Note 3) until the crust is golden brown, 6 to 10 minutes. Remove pizza from the oven with a cookie sheet or pizza peel. Repeat with remaining dough and toppings.