Article from Stampin' Up Blog here, written by Christina N, Stampin' Up Concept Artist:
Christina made an iron-on transfer sheet with My Digital Studio. First, she selected a stamp from MDS’s Halloween Bash Stamp Brush Set and colored it in. Then, Christina mirrored the image in MDS (the image needs to be backwards for it to work with the iron-ons). Next, she printed the images onto iron-on sheets, ironed them to the Mini Muslin Bags, then peeled off the backing.
Christina put treats inside, finished them off with some filler that resembles straw—and was done. Easy peasy.