"The crispy top is a game-changer...."
all-purpose flour, plus more for surface
unsalted butter, cut into 1/2" pieces
granulated sugar
kosher salt
apple cider vinegar
ice water (or more, if needed)
Granny Smith apples, peeled, cored, and cut into medium pieces
granulated sugar
all-purpose flour
kosher salt
ground cinnamon
sour cream
egg
vanilla
firmly packed brown sugar
granulated sugar
all-purpose flour
old-fashioned oats
ground cinnamon
toasted and chopped walnuts
butter, softened