Preheat the oven to 300 degrees F (150 degrees C). Line cookie sheets with parchment paper.
In a medium bowl, stir together the almond paste, egg whites and lemon extract until smooth. Sift together the white sugar and confectioners' sugar, then combine sugars with the flour and salt. Stir the dry ingredients into the egg mixture along with the food coloring of your choice. Drop by teaspoonfuls, two inches apart, onto the prepared cookie sheets. Sprinkle some nuts on top of each cookie.
Bake for 25 to 30 minutes in the preheated oven, until cookies are golden around the edges. Cool for a few minutes on baking sheets before removing to wire racks to cool completely. Store or freeze in an airtight container.