3. Step
Meanwhile, heat a large cast-iron or other ovenproof skillet over medium-high heat (see Tip). Add beef and cook, stirring occasionally and breaking up the meat, until browned, 6 to 8 minutes; drain off most of the fat. Stir in Worcestershire and thyme, then add peas and carrots and onion; cook, stirring, until the vegetables are softened, about 5 minutes. Remove from heat.