Cream margarine and sugar together until light and fluffy.

Beat in eggs, one at a time, until well combined.

Add vanilla extract and mix well.

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

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

Roll the dough out onto a lightly floured surface to your desired thickness.

Cut out cookies using cookie cutters of your choice.

Place cookies on a baking sheet.

Bake in a preheated 350°F (175°C) oven for 10-15 minutes, or until edges are lightly golden.

Let cookies cool completely on a wire rack.

For the icing, mix icing sugar and egg white together until smooth.

Brush the icing over each cookie with a pastry brush.

Let the icing harden completely before serving.