Preheat oven to 350°F (175°C). Grease and line two 9-inch cake pans with parchment paper.

Whisk together flour, baking powder, baking soda, salt, and cinnamon in a medium bowl.

Cream butter, brown sugar, and granulated sugar until fluffy. Beat in eggs one at a time, then add vanilla.

Alternate adding dry ingredients and buttermilk until batter is smooth.

Divide batter evenly into prepared pans and bake for 28–32 minutes until a toothpick comes out clean.

Cool cakes completely on a wire rack.

Prepare filling by melting butter in a saucepan. Stir in brown sugar, maple syrup, cream, and vanilla. Simmer until slightly thickened, then fold in pecans.

Beat butter and cream cheese until smooth. Add powdered sugar, caramel sauce, and vanilla to make frosting.

Layer cakes with pecan filling between layers, then frost entire cake with caramel frosting.

Decorate with toasted pecans and caramel drizzle before serving.