For pastry, beat 1/2 c butter or margarine with cream cheese. Add flour, beating well. Cover bowl and chill for about 1 hour. In a small mixing bowl, combine egg, brown sugar, 1 Tbsp butter, vanilla, and salt, blending just until smooth. Set egg mixture aside. Shape chilled pastry dough into 2 dozen 1-inch balls. Place each ball in an ungreased 1 3/4-inch muffin cup, pressing the dough onto the bottom and sides of the cup. Spoon about 1 tsp of pecans into each pastry cup, and fill with egg mixture. Bake at 325 for 25 minutes or until filling is set. Cool on wire racks before removing from pans.