Begin by grating cold unsalted butter into a large mixing bowl. Add confectioners' sugar, salt, and all-purpose flour, mixing until the mixture resembles coarse crumbs.

Crack a large egg into the flour mixture, followed by a splash of vanilla extract. Stir until a soft, cohesive dough forms.

Divide the dough into three equal portions and use natural food coloring to tint each portion in pastel colors.

Wrap each portion of colored dough in plastic wrap and refrigerate for at least 1 hour.

Preheat your oven to 350°F (175°C). Roll out each colored dough portion to about ¼ inch thick, using cookie cutters to create shapes.

For decoration, cut out smaller shapes from half the cookies and replace them with contrasting colors.

Place the baking sheets in the oven and bake for 12-16 minutes, until edges turn golden brown.

Let cookies cool for about 10 minutes, then if using edible glitter, lightly dampen the tops and sprinkle the glitter.