In a large pot melt butter over medium heat. Add marshmallows turning down burner to a low setting. Stir continually until marshmallows are 75 % melted. Turn off burner. Add food coloring and mix until desired tree color is met and all marshmallows are melted. (Look for a dark green color.)
Place rice krispies into a large bowl. Pour marshmallow mixture over rice krispies and stir with a spatula until all rice krispies are coated and green in color.
Using about 1/4 to 1/3 cup of rice krispie mixture free form a cone shape keeping it flat on the bottom and going to a point at the top to shape the christmas tree. Set the christmas tree onto a parchment or wax paper lined baking sheet. (Work fast to build the trees before mixture solidifies in the bowl.) This batch will make approximately 12 christmas trees.
Let trees sit on baking sheet for 1 hour to set up.
After the 1 hour, set the Reese's peanut butter cup upside down and place about 1/4 tsp of icing or frosting on top. Place the bottom of the christmas tree on top of the icing/frosting pressing down gently to secure. After all of them are secure, let sit for 30 minutes to set up.
Using the icing or frosting form a garland like shape around the christmas tree. (You can also skip this step on several of the trees.) Place m&ms onto the icing on the tree to form the lights. (You can also use corn syrup to secure m&ms on the trees without icing.
Secure a yellow m&m to the top of the tree with icing or corn syrup to create a star.
To secure m&ms on to the tree using corn syrup, just apply using a toothpick.
Place on a christmas plate and dust with powdered sugar to give a snowy look.
Let your imagination run wild. Have fun.
