Mulled Cider with Calvados

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Source: Epicurious

3 cups apple cider (or apple juice)
2 tablespoons firmly packed light brown sugar
1/4 teaspoon ground allspice
1/4 teaspoon ground nutmeg
4 whole cloves
Two 3-inch cinnamon sticks, broken into pieces
1/2 Granny Smith or other tart apple, cored and sliced thin
1/2 cup Calvados (or brandy), or less to taste