1/3 cup spicy brown mustard 2 tablespoons brown sugar 3 tablespoons maple syrup 2 tablespoons yellow mustard 1 tablespoon grated onion $ 1 tablespoon cider vinegar 2 teaspoons lower-sodium soy sauce 1/2 teaspoon black pepper 1 garlic clove, minced $ 8 bone-in chicken thighs, skinned 1/4 teaspoon kosher salt Cooking spray

1. Combine first 9 ingredients. Place half of mixture in a zip-top plastic bag; reserve remaining mixture. Add chicken to bag; seal. Chill 2 hours.
2. Preheat grill to medium-high heat.
3. Remove chicken from bag. Sprinkle chicken with salt. Place chicken on a grill rack coated with cooking spray; grill 8 minutes on each side or until done. Serve with reserved mustard mixture.