In a heavy-bottom pan, melt butter and add onions. Cook over medium-high heat until the onions start to take on some color. Using a wooden spoon, stir the onions around the pan to get all the caramelized bits. Reduce the heat to low and continue cooking and scraping until the onions are a dark golden brown color. Season with salt and pepper.

Place in a sauté pan over low heat. Cook slowly until the bacon has rendered out the fat and is cooked to your desired level of crispiness. Drain off the fat and reserve for decadent crispy potatoes.

Preheat oven to 500° and use a pizza stone if possible. Allow stone to get hot for at least 30 minutes. Place the crust on a well-floured pan that you will be able to slide off into the oven. An upside down half sheet tray or jelly roll pan works well. Make a thin layer almost to the edges of the dough with the fresh and shredded mozzarella cheese. Spread around the onions and bacon lardons. Finish with thin layer of the fontina cheese on top. Slide onto the pizza stone and bake until the cheese is melted and the crust is has cooked through, about 8 to 10 minutes. Use a spatula to lift up one side. The bottom should have a nice golden brown color.