In large skillet over medium heat, heat olive oil. When hot, add onion and garlic; sauté until onion is translucent.
Add ground turkey to pan. Break up meat and stir frequently until meat is browned. Add carrots, green pepper and red pepper. Cook 5 minutes so vegetables can begin to soften.
Add marinara sauce, Worcestershire sauce, ground mustard, kosher salt and black pepper. Stir and bring to boil. Reduce heat so it simmers; partially cover pan. Cook 10 minutes.
Serve on mini buns.