- In a large bowl, cream brown sugar and remaining butter until light and fluffy. Beat in egg yolk and vanilla. Gradually add flour, baking powder and salt and mix well. Cover and refrigerate for 1 hour or until easy to handle.
- Place chopped pecans and 1 tablespoon butter on a rimmed cookie sheet. Bake at 325 degrees, stirring frequently, for 5-7 minutes or until toasted and browned. Set aside and cool.
- Roll into 1-in. balls, then roll in toasted pecans, pressing nuts into dough. Place 2 in. apart on ungreased baking sheets. Beat egg white until foamy. Dip the bottom of pecan halves in egg white, then gently press one into each ball. (If you get the foamy egg white on the top of the pecan it with remain after baking and not be attractive)
- Bake at 375° for 10-12 minutes or until golden brown. Cool for 2 minutes before removing to wire racks.