1. Trace desired size heart or draw freehand hearts onto white paper. Tape paper to cookie sheet or tray. Lay sheet of wax paper over white paper. Freehand hearts may also be piped onto prepared cookie sheets or marble slab.
2. Place chocolate chips in small microwave-safe bowl. Microwave at MEDIUM (50%) 1 minute; stir. If necessary, microwave at MEDIUM an additional 15 seconds at a time, stirring after each heating, until chips are melted and smooth when stirred.
3. Spoon melted chocolate into small squeeze bottle, pastry bag or strong resealable plastic food storage bag fitted with writing tip.* Pipe hearts onto prepared trays or marble slab. Refrigerate about 30 minutes or until firm.
*Plastic food storage bags can be used without the writing tip. Simply fill bag and then snip off a very small section of one bag corner.