Preheat the oven to 375 degrees F (190 degrees C). Line mini muffin pans with paper liners.

In a medium bowl, stir together the cream cheese, 1/2 cup butter and flour until a dough forms. Roll into 1 inch balls and press them into the bottom and up the sides of the prepared muffin cups.

In a small bowl, blend together the egg, butter, vanilla and brown sugar until smooth. Stir in walnuts. Spoon the mixture into the muffin cups, but do not fill all the way to the top or the mixture will bubble over.

Bake for 15 to 20 minutes in the preheated oven, until the crusts are golden.