To a mixing bowl, add cubed butter and cream cheese. Using a pastry cutter, cut flour into the butter and cream cheese until the mixture resembles coarse crumbs. Using your hands, work the mixture into a dough. Form the dough into an even log or brick shape. Chill the dough for 1 hour.
While the dough chills, beat together egg, brown sugar, 1 tablespoon butter, vanilla, and salt.
Assembling the Cookies
Preheat oven to 325 degrees.
Cut the chilled log of dough in half. Cut each half in half again, and so on until there are 24 one-inch equal portions of dough. Shape each piece of dough into a circle and press into ungreased miniature muffin pans.
Divide half of the pecans between the 24 pastry filled cups. Top each with filling, being careful not to overfill. Top each cup with remaining pecans.
Bake for 25 minutes or until filling is set. Let cool before removing from pans. Store in an airtight container.