Heat oven to 375 degrees F. Line two baking sheets with parchment.
In a medium bowl, combine gluten-free flour, cocoa, cornstarch, baking soda, salt and baking powder.
In a large bowl, combine butter, shortening and both sugars. Beat until well blended and smooth, about 2 minutes. Add eggs, one at a time, until blended.
On low, gradually beat in dry ingredients until smooth. Beat in vanilla and zest. Fold in chocolate and cranberries.
Scoop mounds of dough onto prepared sheets. Bake at 375 degrees F for 13 to 15 minutes per batch. Cool on sheets on wire racks for 5 minutes. Transfer directly to racks; cool completely.