
Preheat oven to 350 degrees F (175 degrees C).
Mix water, onion, olive oil, balsamic vinegar, Dijon mustard, garlic, black pepper, cayenne pepper, and salt together in a roasting dish.
Add chicken; turn until well coated with mixture.
Bake in the preheated oven until an instant-read thermometer inserted into the thickest part of the thigh, near the bone, reads 165 degrees F (74 degrees C), about 1 hour 30 minutes.

Water
1 cup

Onion
1 chopped

Olive Oil
5 tablespoons

Balsamic Vinegar
2 tablespoons

Dijon Mustard
1 tablespoon

Garlic
3 Cloves Crushed

Black Pepper
1 tsp

Cayenne Pepper
1 tsp

Salt
To taste

Chicken
1