I won a holiday cookie contest 20 years ago with this recipe given to me by a good friend. It has been a family favorite and a regular in our Christmas cookie line-up. The dough has a soft texture and is not too sweet.
For the dough, cream the butter, sugar, corn syrup and egg yolks. Stir in flour gradually to mix. Chill 1 hour.
For the filling, combine confectioners' sugar, butter and and dark corn syrup in a saucepan. Cook over medium high heat until mixture comes to a full boil. Cook for two minutes. Remove from heat. Stir in pecans. Set aside until cool enough to handle. Mixture thickens when cool.
Preheat oven to 375 degrees. Make walnut size balls of dough and place on a parchment covered cookie sheet. Brush with reserved egg white. Bake for 5 minutes. Remove from oven and press 1/2 teaspoon of pecan filling into center of each partially baked cookie. This is easiest to do using your fingers. Return to oven for 5 more minutes. Cool for 3 minutes on baking sheet then remove to cooling rack.