Pulse 1 medium onion, chopped, 1 celery stalk, chopped, and 1 small carrot, peeled, chopped, in a food processor until very finely chopped. Transfer to a small bowl.
Heat 3 Tbsp. extra-virgin olive oil in a Dutch oven or other large pot over medium. Break 1 lb. ground beef chuck (20% fat), patted dry, into small clumps (about 1½") and add to pot; season lightly with kosher salt. Cook, stirring occasionally but not breaking meat apart, until beef is lightly browned but not crisp, 6–8 minutes. It may be gray in spots (that’s okay!) and still a little pink in the center. Using a slotted spoon, transfer beef to a medium bowl.
Wipe out pot. Cook 3 oz. thinly sliced pancetta, finely chopped, in same pot over medium heat, stirring occasionally, until pancetta has released some of its fat and is crisp, 6–8 minutes. Add reserved onion mixture to pot and cook, stirring occasionally, until vegetables are very soft and beginning to stick to surface, 6–8 minutes.
Return beef to pot and pour in 1 cup dry white wine. Reduce heat to medium-low and cook, smashing beef with a wooden spoon, until wine is evaporated, surface of pot is almost dry, and meat is finely ground, 12–15 minutes. (The meat should be reduced to what looks like little bits. It takes a bit of effort, but you can take breaks.) Add ⅓ 1 and one of and cook, stirring occasionally and still pressing down on meat, until is slightly darkened, about 5 minutes.