Preheat oven to 350 degrees. Spray the inside of a shortbread mold or 9-inch baking pan with cooking spray, and set aside.
Cream together butter and sugar in a large bowl.
Cut or beat in the flour. If dough is too crumbly, add an additional 1 to 2 Tablespoons of softened butter until it holds together.
Place dough into pan and smooth out evenly.
Bake for 25 to 30 minutes, until set and lightly browned.
Remove from oven and allow to sit for 5 minutes.
Run a thin knife around the edges to loosen them, then flip shortbread out onto a wire cooling rack.
Using a sharp chef knife, cut into wedges.
Allow to cool and serve with your favorite tea.
If you would like to decorate your shortbread: Mix edible glitter and a small amount of vodka together in a small bowl. You want it thin enough to "paint", but not so diluted that there is no color. Use a clean paintbrush to paint on your design.