Add 5 cups mini marshmallows and 3 tablespoons butter to a large, microwave safe bowl.
Microwave the butter and marshallows about 3 minutes, or until warm and very puffy.
In another large bowl, measure 4 1/2 cups rice krispies cereal.
Carefully remove marshmallows from microwave and add yellow food coloring (I used 2 drops of yellow Americolor gel).
Stir the melted marshmallows, butter and coloring until smooth and fully combined. Immediately, pour the marshmallow mixture into the bowl with the cereal. Use an oiled spatula and stir quickly until fully incorporated.
Divide yellow rice krispie mixure between the two cake pans, and use your hands to create a "ring" around the inside edge of the cake pan (as shown below), about 1 1/2 inches wide. Rub a bit of butter on your hands as necessary to prevent the mixture from sticking to your hands. Work quickly, as the mixture is more difficult to mold as it cools.
Wash your bowls and spatulas and repeat the same process with the ingredients for the orange ring, and then the white center.
Once your three colors are pressed into the pans, allow to fully cool and set, at least 30 minutes. When you want to cut the triangles (candy corn shapes), flip over your cake pans onto a cutting surface, and tap pan on cutting board to remove krispie treat round. Cut the round large round in half, then quarters, then cut each quarter in half.
To add a cookie stick, or paper straw (as shown), first create a hole with a wooden skewer.