Line a plate with paper towels and set aside. Place the pancetta in a large frying pan with a tightfitting lid and cook uncovered over medium heat until browned and crispy, about 10 minutes. Transfer with a slotted spoon to the prepared plate, leaving the fat in the pan. Add shallots and garlic to the pan, season with salt and freshly ground black pepper, and cook, stirring occasionally, until vegetables are softened and edges begin to brown, about 3 minutes. Add Brussels sprouts, season with salt and pepper, stir to coat, and cook until just browned, about 3 minutes. Pour in wine, scraping up any browned bits from the bottom of the pan, and cook until wine reduces by half, about 2 to 4 minutes. Pour in broth, cover, and reduce heat to low. Cook until Brussels sprouts are knife tender, about 20 minutes. Taste, adjust seasoning as desired, transfer to a serving dish, and sprinkle with reserved pancetta.