In a large bowl beat butter till softened. Add brown sugar and molasses and beat until fluffy. Add flour and beat until well mixed. Stir in pecans. Shape dough into 1-inch balls. Place on ungreased cookie sheets. Bake in 325 degrees oven for about 20 minutes or until done. Remove and cool. In a plastic bag gently shake a few at a time in powdered sugar. Makes 56 cookies.