Preheat oven to 400 degrees with the oven rack in the middle. Heat a cast iron (or heavy bottom skillet) over medium high heat.
Pat the chicken thighs with a paper towel to remove any moisture, this will allow them to get a crispy, golden skin. Season both sides of the chicken generously with salt and pepper.
When the skillet is hot, add the olive oil and the chicken thighs skin side DOWN. Cook for 3-5 minutes until the skin is crispy, golden brown. Remove the chicken from the skillet and transfer to a plate skin side UP.
Add the sliced onion to the warm skillet, and season with 1/2 teaspoon salt and pepper. Cook 3-5 minutes until the onions are starting to turn translucent. Add the garlic and cook for 30 seconds until fragrant.
Add the white wine (or chicken stock) and dijon mustard. Stir to combine, and scrape up any brown bits on the bottom of the pan.
Add the chicken back in to the skillet skin side UP (so it stays crispy), then add in the grapes around the chicken thighs.
Braise the chicken thighs in the oven until the chicken reaches an internal temperature of 165 degrees with an instant read thermometer, about 25-30 minutes.
Remove from the oven, and serve the chicken warm with the sauce and dairy free mashed potatoes and a roasted vegetable. Leftovers will keep in an airtight container for 5 days.
Calories: 567 | Total Carbs: 70.7g | Protein: 42.1g | Fat: 13g | Fiber: 10g | Net Carbs: 61g