1/2 cup (8 tablespoons) unsalted butter, at room temperature
1/2 cup granulated sugar
1/4 cup dark brown sugar, packed
1 large egg
1 cup plain low-fat yogurt (not Greek-style)
1 cup whole wheat flour, spooned into measuring cup and leveled-off with back edge of knife
1 cup all-purpose flour, spooned into measuring cup and leveled-off with back edge of knife
1 teaspoon baking powder
1 teaspoon baking soda
Heaping 1/4 teaspoon salt
1 tablespoon ground cinnamon
1/2 teaspoon ground nutmeg
1/4 teaspoon ground cloves
2 cups peeled, cored and finely chopped baking apples (you'll need 2 large apples)
6 tablespoons dark brown sugar, packed