Christmas Tree Rice Krispies Treats

salted butter, (diced into 1-Tbsp pieces)

bag mini marshmallows

Green gel food coloring ((such as Wilton brand))

Rice Krispies cereal

White decorating icing ((I just used store-bought))

miniature Reeses peanut butter cups, (unwrapped*)

Round red sprinkles

star sprinkles or yellow mini M&Ms