In a mixing bowl, cream together ½ cup softened butter and 3 oz softened cream cheese until smooth.
Gradually blend in 1 cup of flour. Shape dough into 1-inch balls and press into mini muffin pan to form cups.
In another bowl, mix together 1 cup finely chopped pecans, 1 beaten egg, ¾ cup packed brown sugar, 1 tablespoon melted butter, and 1 teaspoon vanilla extract.
Spoon filling into each dough cup. Bake for 25 minutes or until filling is set.
Cool in pan for 10 minutes, then remove and cool completely on a wire rack.