Step 1

Preheat the oven to 325 degrees F. Line baking sheets with parchment paper or baking mats.

Step 2

Cream the butter and sugar together. Sift in the flour and cornstarch and blend using a pastry cutter until the ingredients all come together. (If the mixture seems excessively dry, cut in 1 more tablespoon of butter--but only if you really need it.) Form the dough into a big ball, wrap in plastic wrap and refrigerate 20 minutes.

Step 3

Roll onto a lightly floured surface and cut into rounds with a 3- or 4-inch round or fluted cookie cutter. Place on the prepared baking sheets. Bake for 20 minutes. Do not allow the shortbread to brown; check your oven sooner if it runs hot. Let cool.

Step 4

Melt the chocolate in a bowl over a pan of boiling water, or in a microwave. Once the shortbread cookies have cooled, spoon a little chocolate onto each cookie, spread it out and sprinkle over some sprinkles! Allow the chocolate to harden for an hour before eating, storing or packaging.