Whisk together pastry or all purpose flour, corn flour, cocoa powder and salt together, set aside.

Using a stand mixer, hand held mixer or wooden ladle, beat margarine or butter, oil and granulated sugar together until just combined. Add the egg and vanilla and mix just until incorporated. Gradually add the flour to form a smooth dough.

Preheat an oven to 180˚C/ 350˚F. Roll the dough to a thickness of 3/8-inch, between two sheets of parchment or baking paper. Cut shapes using a cookie cutter. Bake on baking sheets lined with baking or parchment paper for 12 to 15 minutes, or until the cookies look dry on the surface, and feel firm around the edges and set. Cool completely, then decorate as desired.

Cookies can be stored in an airtight container at room temperature for seven days and unbaked cookie dough can be kept in the freezer for three months.