Spray an 8×8 square pan with cooking spray. Set it aside.
Whisk 1 package of gelatin mix, 1/4 cup boiling water and 1 container of yogurt in a medium microwaveable bowl until blended.
Microwave on high setting for 2 minutes, stirring after each minute. Pour into prepared pan. Refrigerate 40 to 45 minutes or until set but not firm.
Repeat this process with each remaining gelatin flavor to make a total of 3 layers, refrigerating as directed after adding each layer.
Then refrigerate it for 2 hours or until firm. Remove it from the pan onto a cutting board. Cut gelatin into 12 slices or cut with your preferred shape of cookie cutters.