Preheat the oven to 375 degrees F (190 degrees C). Line mini muffin pans with paper liners.
In a medium bowl, stir together cream cheese, ½ cup butter, and flour until a dough forms. Roll into 1-inch balls and press into the bottom and up the sides of the prepared muffin cups.
In a small bowl, blend together egg, butter, vanilla, and brown sugar until smooth. Stir in walnuts. Spoon mixture into the muffin cups, filling each ¾ full.
Bake in the preheated oven for 15 to 20 minutes, until crusts are golden.
