For me, it doesn't get better than a four-ingredient dish. I also love that this side tastes decadent but is actually good for you! The salty pancetta adds richness to the crunchy sprouts and a splash of vinegar brightens the whole thing up.
Heat the olive oil in a large skillet over medium heat. Add the pancetta and cook, stirring often, until, rendered and crisp, about 6 minutes. Transfer with a slotted spoon to a paper-towel lined plate to drain.
Increase the heat to medium-high and add the Brussels sprouts, 1/2 teaspoon salt, and a few grinds of pepper. Cook, stirring often, until bright green and slightly wilted, 2-3 minutes. Drizzle in the vinegar and toss well to coat.
Transfer to a bowl and top with the pancetta.