First, you make a batch of sugar cookie dough. Then you color it with red food dye.
Roll the cookie dough out. Cut the cookies out into circles. Cut the circles into halves (like watermelon halves).
Press mini chocolate chips into the cookies and bake at 350 degrees until lightly browned around the edges. While cookies are baking, tint some white icing with green food dye. After the cookies are removed from the oven and have cooled. Drag the "rind" part of the cookie through the green icing.
These are Little Guy's watermelon cookies that he made all by himself...
Big Guy was thrilled and the entire plate was gone before bedtime!