Mary Seldon's Sandwich Cookies

In large bowl, beat together butter, granulated sugar, vanilla sugar and salt until light and fluffy. Beat in egg yolks, 1 at a time, beating well after each addition; beat in lemon rind. Stir in flour, 1/2 cup (125 mL) at a time, until blended. Shape dough into disk; wrap in plastic wrap. Refrigerate for 1 hour or until firm.

On lightly floured surface, roll out dough to 1/4-inch (5 mm) thickness. With 2-inch
(5 cm) round scalloped cookie cutter, cut out cookies with a 1/2-inch (1 cm) round cookie cutter, cut centred circle out of half the cookies. Transfer to greased or parchment paper–lined rimless baking sheets. In small bowl, gently whisk egg white; brush over cut-out cookie tops.

One sheet at a time, bake in centre of 325°F (160°C) oven for 10 to 12 minutes or until bottoms are light golden. Transfer to rack; let cool. Sprinkle icing sugar onto cookie tops. Spread 1 tsp (5 mL) jam onto remaining cookies; top each with cutout cookie.

Source : Canadian Living Magazine: December 2000