Heat oven to 375°F.
Combine 1 cup butter, sugar and vanilla in bowl. Beat at medium speed until creamy. Add flour and salt; beat at low speed until mixture forms a dough.
Place pecans into bowl. Shape rounded teaspoonfuls of dough into 1-inch balls. Dip each ball in beaten egg white; roll in pecans. Place 1 inch apart onto greased cookie sheets. Make indentation in center of each cookie with thumb or back of teaspoon. Bake 11-13 minutes or until very lightly browned and set. Cool 1 minute on cookie sheet; remove to cooling rack. Cool completely.
Combine powdered sugar, 3 tablespoons butter, half & half and maple extract in bowl. Beat at low speed until smooth. Fill center of each cooled cookie with
For easy clean-up, shape all the balls for 1 cookie sheet, then use 1 hand to roll them in egg whites and your other hand to roll them in pecans. Wash hands and start again for the next sheet.