115gm (1 stick) Unsalted Butter, melted and cooled
6 large Apples peeled and thinly sliced
additional butter and flour for preparing the pan
Preheat oven to 350°. Butter and flour a tube pan.
First, make the crumb topping. Whisk together flour, brown sugar, cinnamon, and salt in a small bowl. Pour in the melted butter and stir with a fork until large clumps form. Set aside.
In a large bowl, whisk together flour, baking powder, salt, cinnamon, and nutmeg. In a medium bowl, whisk together the eggs, sugar, vanilla, sour cream, and butter. Pour the wet ingredients into the flour mixture and stir until just combined. Fold in the apple slices.
Dollop the cake batter into the prepared pan. Spread with a spatula to evenly distribute the apples and create a fairly level top. Sprinkle clumps of the crumb topping evenly over the top of the cake.
Bake until a tester inserted in the center of the ring glides through the apples and comes out free of cake batter, about 1 hour, 5-10 minutes. I would start checking at 50 or 55 minutes as apple cake baking times tend to vary based on size/variety of apples used.
Cool the cake for 10-15 minutes in the full pan, then remove the outer portion and allow to cool at least another 15 before you attempt to pull it off the pan completely. Serve the cake warm, sprinkled with powdered sugar, with a scoop of ice cream, or a dollop of whipped cream.