Preparation

• Line a 9 inch springform pan with parchment paper and set aside. Preheat the oven to 350 degrees F.
• In a medium bowl, combine diced apples, brown sugar, cinnamon, and cornstarch. Toss together and set aside.
• In a small bowl, mix together brown sugar, flour, cinnamon, and melted butter to form a crumbly texture for the crunch topping. Set aside.
• In a large mixing bowl, whisk together brown sugar, sugar, and oil until smooth, then add eggs, vanilla extract, and sour cream. Whisk until smooth.
• In a separate bowl, whisk together all purpose flour, baking powder, cinnamon, nutmeg, allspice, and kosher salt. Add dry ingredients to wet ingredients and mix until combined.
• Fold half of the apple mixture into the batter. Pour batter into the prepared pan, add remaining apples on top, and sprinkle crumble on top. Bake for 1 hour and 15-25 minutes, until a toothpick comes out clean.
• While the cake bakes, make the glaze by whisking together confectioners' sugar, milk, vanilla, melted butter, and cinnamon.
• Allow the cake to cool for 15 minutes, then remove to a wire rack. Pour glaze over the warm cake and cool for 25-30 minutes before slicing.