Melt butter and marshmallows in a 2-quart saucepan over low heat, stirring constantly until smooth.

Remove the saucepan from heat.

Stir in red and yellow food coloring until the mixture turns orange.

Add Cheerios cereal to the melted marshmallow mixture and stir until evenly coated.

Shape approximately 1/3 cup of the cereal mixture into a ball.

Press a whole cashew into the top center of the ball to resemble a stem.

Repeat steps 5 and 6 with the remaining cereal mixture and cashews.

Let the shaped cereal balls stand for at least 15 minutes, or until firm.

Decorate the Jack O' Lanterns with raisins, gumdrops, or candy-coated chocolate candies using white decorating icing to adhere them.