• Preheat oven to 450 degrees. Grab a sheet pan with some sides.
• Thinly slice the cabbage and the red onion and set aside.

For the chicken

• In a large plastic bag mix 3 tbsp mustard, only 1 tbsp maple syrup, some pepper.
• Drain or pat chicken dry if needed and toss in bag with mustard mix, smoosh around to cover all pieces.
• Roast skin side up for 20 minutes until skin has begun to crisp. I tend to turn oven down to 400 if browning too fast. You want the chicken more than halfway cooked here, not just browned skin.
• Remove from oven and turn oven down to 375. Remove chicken onto a plate and either discard fat or keep it in pan for flavor.

For the cabbage

• In a large bowl combine the cabbage, 1 red onion, 4 tbsp apple cider vinegar, 1 tbsp olive oil, remaining 2 tbsp maple syrup, salt and some pepper.
• Put cabbage mix into the pan and also return the chicken to the pan, snuggling the chicken into the cabbage, not set on top.

Final cooking

• Roast 20 to 25 minutes, until cabbage softens, and chicken is fully cooked. Chicken can be removed at any point if overcooking while cabbage cooks on. I like the cabbage still crispy, not too soggy, so I try to cook chicken mostly on first step and then less time on this step to keep cabbage al dente.
• Add some salt, pepper to taste to cabbage, serve warm.