Claim Jumper Whiskey Chicken

3/4 stick butter
1/2 cup celery, diced
1/2 cup onion, diced
2 cups chicken stock
1/4 teaspoon dried thyme
1/2 teaspoon dried basil
1/4 teaspoon granulated garlic
1/4 teaspoon plus 1 pinch white pepper
10 ounces sourdough croutons
1 1/2 Granny Smith apples, diced
1 teaspoon dried tarragon
1 tablespoon freshly-chopped parsley
4 double chicken breasts, skin-on
1 cup apple juice
1/4 cup brandy
1/4 cup whiskey
4 tablespoons granulated sugar
1 pinch fresh tarragon leaves
1 pinch ground nutmeg

Melt butter in a saucepan. Saut