Preheat the oven to 350?F (175?C).

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Beat in the egg and vanilla extract until well combined.

In a separate bowl, whisk together the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Divide the dough into portions and add food coloring to each portion as desired.

Roll out the dough on a floured surface to about 1/4 inch thick.

Cut out shapes using cookie cutters and place them on a baking sheet lined with parchment paper.

Bake for 8-10 minutes or until the edges are lightly golden.

Allow cookies to cool completely on a wire rack.

In a mixing bowl, combine powdered sugar, egg white (or meringue powder), and lemon juice.

Beat until the icing is smooth and holds stiff peaks.

Transfer the icing to piping bags and decorate the cooled cookies as desired.