Place a small pot over medium-high heat with the sugar and white balsamic vinegar. Bring up to a bubble, stirring frequently to dissolve the sugar. Place the onions in a large heat-safe bowl and pour the sugar-vinegar mixture over them. Stir to combine and let the onions rest for at least 15 minutes.

While the onions are resting, place a large skillet over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Add the ground pork to the pan, season with salt and pepper, and cook until golden brown, about 7-8 minutes, breaking the meat up with a wooden spoon or potato masher.

Add the fennel seeds, red pepper flakes, peppers and garlic to the pan and cook until the peppers are tender, about 5 minutes. Add the tomato paste and cook until golden and aromatic, about 1 minute. Add the wine to the pan and scrape up any bits that may be stuck to the bottom of the pan. Cook until almost completely evaporated, about 2 minutes. Add the chicken stock to the pan and bring up to a bubble. Season with salt and pepper, and simmer until thickened to a Sloppy Joe consistency, about 10 minutes.