Preheat oven to 350. Generously grease 2 9-inch cake pans with shortening and lightly dust with flour. Set aside.
Prepare the Pecans
In a large bowl, toss pecan chips with melted butter and cinnamon.
Place in a single layer on a baking sheet and bake at 350 for 6 minutes, flipping halfway. Pecans should be fragrant & slightly crunchy when removed from the oven. They will become crunchier as they cool.
Let pecans cool on the pan once cooled, removed 1/2 cup of pecans, and blend in a food processor until creamy. Set aside until ready to use.
Make the cake!
In a medium bowl, sift together flour, baking powder, and salt. Set aside.
In a large bowl, cream together granulated sugar, brown sugar, and butter.
Mix in eggs and egg yolk.
Mix in vanilla extract, maple extract, and sour cream.
Mix the dry ingredients into the wet ingredients, alternating with the milk.
Once batter is combined and fluffy, stir in the pecan butter and 1/2 cup of the butter pecan chips (reserve the other 1/2 cup for the frosting)
Pour batter evenly into prepared pans and bake for 25-28 minutes or until a toothpick inserted into the center comes out clean (may need more or less time so check on it at the 25-minute mark)
Allow the cakes to cool in the pan until the pans are cool enough to touch, and then carefully, remove them from the pans and allow them to cool completely on a cooling rack.
Make The Frosting
In a large bowl, cream together cream cheese, and butter.
Add brown sugar and mix until fluffy and light. (The brown sugar should be completely mixed in and creamy without a gritty texture)
Mix in vanilla extract, maple extract, and a pinch of salt.
Gradually mix in powdered sugar until frosting is smooth and creamy.