3/4 cup (packed) dark brown sugar
1 cup unsalted butter (softened, divided into 1/2 stick and 1-1/2 sticks)
2 tablespoons honey or agave syrup
1 1/4 pounds crisp, tart apples, such as Fuji or Granny Smith, (peeled and cut into 1/4-inch-thick slices)
3/4 cup granulated sugar
3 large eggs
2 teaspoons pure vanilla extract
1 1/2 cups unbleached all-purpose flour
1 tablespoon ground cinnamon
1 1/2 teaspoons salt
1 cup milk
1 1/2 teaspoons baking powder