Preheat the oven to 350°F.
Grease a 9x13-inch baking dish thoroughly with butter or nonstick cooking spray.
In a small skillet over medium heat, melt 1 tbsp butter.
Add the roughly chopped pecans.
Stir and cook for 3 to 4 minutes, or until the pecans are lightly toasted and fragrant.
Remove the skillet from the heat and set the pecans aside.
In a large mixing bowl, combine the white sugar and 1 c softened butter.
Beat until the mixture is light and fluffy.
Add the eggs one at a time, beating well after each addition.
Add the vanilla extract and maple extract.
Mix until fully incorporated.
In a separate large bowl, combine the all-purpose flour, baking powder, and salt.
Stir until evenly mixed.
Gradually add the dry mixture to the butter mixture, alternating with the whole milk.
Mix just until combined.
Fold in the toasted pecans.
Transfer the batter to the prepared baking dish.
Spread the batter evenly.
Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
Remove the cake from the oven.
Allow it to cool until it is safe to handle.
While the cake cools, prepare the frosting.
In a large mixing bowl, combine the powdered sugar, cream cheese, softened butter, vanilla extract, and maple extract.
Beat until smooth and creamy.
Add 1 to 2 tbsp milk, as needed, until the frosting reaches a spreadable consistency.
Once the cake has cooled enough to handle, divide it in half.
Scoop one half of the cake into a large bowl and crumble it into small pieces.
Add approximately 1/4 of the frosting to the crumbled cake.
Stir until the crumbs are evenly moistened.
Repeat the same process with the remaining half of the cake.
Transfer the moistened cake crumble mixture back into the baking dish.
Press the mixture into one even layer.
Spread the remaining frosting evenly over the top.
Sprinkle with additional chopped pecans, if desired.
Refrigerate for at least 4 hours, or overnight, until fully set.
Once firm, cut into small squares.
Serve chilled.