This warming skillet supper comes together quickly in a single pan for an easy weeknight dinner. Serve it the traditional way on a toasted bun, or spooned over steamed rice, quinoa or a baked sweet potato.
Heat the oil in a large skillet over medium-high heat. Add the onion, carrot and celery and cook until translucent, about 3 minutes. Add the ground beef with the salt and pepper and cook, braking it up with a wooden spoon, until it is no longer pink, about 4 minutes.
Add the garlic and tomato paste and cook until fragrant, about 1 minute, then add the tomatoes, Worcestershire sauce, sugar and sriracha. Reduce the heat to low and simmer until thickened, about 12 minutes. Taste for seasoning.
Meanwhile, toast the buns. Portion the sloppy joe mixture onto each bun and top with scallions, if desired.