Directions:  1 Grind the 1/2 cup pecans in a blender, food processor, or food grinder.  2 Combine the nuts with the flour and baking powder.  3 In a separate bowl beat butter and shortening with an electric mixer for 30 seconds.  4 Add the sugar and beat until fluffy. Add egg, sour cream and vanilla and beat until well mixed.  5 Stir in the flour, baking powder and the ground nuts.  6 Divide dough in half. Cover and chill at least 3 hours.  7 Preheat oven to 375 degrees F.  8 Work half of the dough at a time. Keep the other half refrigerated. Roll dough to 1/8-inch thickness on a lightly floured surface. Cut with desired cookie cutter.  9 Place on an ungreased cookie sheet and bake 7-8 minutes or until done. Remove from sheet and cool on a rack.  10 To make lemon glaze: Beat 1 egg white until frothy. Add 1 1/2 cups sifted powdered sugar, 1 tablespoon lemon juice and a dash of salt. Beat well.  11 Spread cookies with Lemon Glaze and sprinkle with nuts. Makes 7 dozen