Preheat the oven to 375 degrees.
In a large skillet melt 1 and 1/2 tablespoons of butter over medium heat. Season the chicken generously with salt and pepper; cook, skin-side down, until golden, about 8 minutes.
Turn the chicken, add the cider, then place the pan in the oven and roast for 20 minutes.
After the pan comes out of the oven transfer the chicken to a plate. Whisk the mustard and sage into the cider drippings; season to taste with salt and pepper. Pour the sauce over the chicken.
While the chicken is cooking, In another skillet, cook the apples in the remaining butter over medium-high for 5 minutes. Add the remaining tablespoon of apple cider, turn the heat to high and cook for 1-2 minutes more. Season the apples to taste with salt and serve them alongside the chicken.