In a mixing bowl, beat together butter and cream cheese until smooth. Add flour and mix until combined. Shape dough into 1-inch balls and press into mini muffin tin to form a crust.
In another bowl, mix together brown sugar, walnuts, melted butter, vanilla extract, maple syrup, and beaten eggs. Spoon filling into each crust.
Bake for 20-25 minutes or until filling is set. Let cool before removing from the tin.