[header] How to make watermelon sandwich cookies [title] Combine all of the ingredients for the frosting in a mixing bowl. [title] Beat the ingredients at medium speed with a handheld mixer or a stand mixer with a paddle attachment. [title] Cover the mixing bowl with plastic wrap and place it in the refrigerator until you are ready to assemble the cookies. 
[title] Preheat a griddle or nonstick skillet and spray it with nonstick cooking spray. [title] Whisk the flours, baking powder, baking soda, sugar and salt in a mixing bowl.