In a medium mixing bowl, beat the 1/2 C. butter and the cream cheese with an electric mixer until well mixed. Stir in flour. Divide dough into 24 balls, 1 inch in diameter, and press the dough evenly into bottom and up sides of twenty-four 1-3/4-inch muffin pans. Bake in a 325 degree F. oven for 10 minutes. Combine the 1/2 C. brown sugar, the pumpkin, egg yolk, cream or milk, the 4 tsp. butter, rum or rum flavoring, vanilla, cinnamon, and nutmeg. Spoon into warm pre-baked cups. Stir together pecans, 1/4 C. brown sugar, and 1 Tbs. butter; sprinkle over pumpkin mixture. Bake in the 325 degree F. oven 25 minutes. Cool in pans for 10 minutes. Loosen and remove C. from pans. Serve warm or cool.