1. Sift flour with baking powder, baking soda and salt.
2. In large bowl of electric mixer, beat margarine, sugar and egg at medium speed until light and fluffy. At low speed, beat in sour cream, lemon extract and grated lemon peel until smooth.
3. Gradually add flour mixture, beating until well combined. Form dough into a ball, wrap in foil and refrigerate overnight.
4. Divide dough into 4 parts. Refrigerate until ready to roll out. On floured surface roll dough, one part at a time, 1 cm thick. Using a 2 to 8 cm cookie cutter or glass, cut out cookies. Use a spatula to carefully pick up and place cookies on a lightly greased cookie sheet 5 cm apart.
5. Lightly brush cookies with lemon juice and sprinkle with additional sugar. Use colored sugar for decorative look.
6. Bake in preheated 375-degree oven for 10-12 minutes until golden brown. Do not overcook. Remove cookies to wire rack to cool completely. Complete baking using one part cookie dough at a time, greasing the pan each time.