• Preheat oven to 350 degrees F.
• In a large mixing bowl, cream butter, 1 cup of sugar and the powdered sugar. Add vegetable oil and eggs and mix well.
• In a separate bowl, combine cornstarch, baking soda, cream of tarter, salt, cocoa and flour and stir to mix..
• Add to wet ingredients to the dry ingredients and mix until well incorporated.
• Roll dough into 1-2 inch balls and place on cookie sheet. I used a large scoop that holds about 1/3 cup of dough
• Put ¼ c of sugar into a bowl.
• Dampen the bottom of a smooth bottomed glass and press it into the sugar to coat the bottom of the glass. Then press the sugar-coated-glass into the cookie dough balls and lightly press down until your dough begins to flatten and the edges around the glass begin to split.
• Bake at 350 degrees F for 8 minutes.
• Cool cookies on a cooling rack and then put them in the fridge until you are ready to frost them.

CHOCOLATE FROSTING

• Combine butter, powdered sugar, cocoa and heavy cream in a medium mixing bowl and beat until smooth. Add vanilla and mix until smooth.
• Frost cooled cookies.