Thoroughly cream butter and sugar; add egg and beat well. Add almond extract. Stir in flour. Pinch off a small ball of dough and place in center of small tartlet mold with thumb, press dough evenly and as thinly as possible over bottom and sides. Place molds on cookie sheet. Bake at 350 F about 12 minutes or till lightly browned. Cool. To remove: Invert molds and tap lightly. (clean molds with dry cloth only). Before serving, fill tarts with whipped cream, jam, or preserves, as desired.
Preheat oven to 350 F. Line baking sheets with parchment paper or a non-stick baking mat. In a large bowl, beat together butter and sugar until light and fluffy. Beat in egg yolks, vanilla extract and salt. Gradually stir in flour. Form dough into 1-inch diameter balls. Dip in lightly beaten egg whites, then roll in nuts. Place 1 inch apart on prepared cookie sheets. Press down center of each with thumb. Bake for 16 to 18 minutes, or until golden brown. Cool on baking sheet for 5 minutes, then remove to a wire rack to cool completely. Just before serving, fill centers of cookies with jam. Or, fill centers with 1/2 teaspoon of jam before baking.