You can't get simpler than this. Well, maybe...but than you would just have a paper plate.
Bonus: this is a kids craft that you won't mind hanging up.
(You know what I am talking about!)
paper plate, green felt, red pompoms, red ribbon, scissors, glue
Fold paper plate in half.
Cut out center along embossed edge.
Cut out leaf shapes from felt.
Tip: cut out rectangles first so all your leaves will be aprox. the same size. Also don't make them too small or you'll be cutting leaves until Valentines day. Fold leaves rectangle in half and cut out half a leaf shape. Open up and you should have a symmetrical leaf.
Give your kiddo the leaves and the glue. Let them glue the leaves on. Let them know that they can overlap the leaves and that they are trying to hide the white plate. After they glue on the leaves you can have them glue on the red pompoms (you can use sequins, buttons...)
Tie a wide ribbon around top to create a pretty hanger (see picture.)