Prepare the Cake Layers:
Preheat your oven to 350°F (177°C) and prepare three 8-inch round cake pans. Beat the butter and sugar until fluffy. Add the sour cream and vanilla. In a separate bowl, whisk the dry ingredients (flour, baking powder, spices, salt). In another bowl, combine the apple butter and milk. Alternate adding the dry and wet ingredients to the butter mixture. Fold in the pecans, then gently fold in the egg whites. Divide the batter between the pans and bake for 22-25 minutes. Let cool completely.

Make the Caramel Sauce and Frosting:
To make the caramel, melt the 1 ½ cups of sugar in a saucepan over medium heat. Add the butter and whisk until combined. Remove from heat and slowly whisk in the room temperature heavy cream. Let cool completely. To make the frosting, beat the cooled caramel sauce with the powdered sugar and milk until smooth and creamy.

Prepare the Cinnamon Apples:
In a small saucepan, combine the chopped apples, brown sugar, spices, lemon juice, and butter. Cook over medium heat for 5-7 minutes, until the apples are tender. Let cool.

Assemble the Cake:
Place the first cake layer on a serving plate. Spread a layer of caramel frosting over the top, creating a “dam” around the edge. Fill the center with half of the cinnamon apples and a sprinkle of pecans. Repeat with the second layer. Place the final cake layer on top and frost the entire cake. Drizzle with any leftover caramel sauce and top with more pecans for decoration.