Pour 1 cup of xylitol into a pot and heat on low. Break up any clumps that may have formed in the xylitol with a spatula. Mix with the spatula to ensure even heat distribution. As it slowly melts, it will turn translucent, then finally transparent. This will take 5 minutes or so.
Take off the heat and add extract and food coloring. Mix until combined evenly.
Begin to place into the molds. Move as swiftly as possible, as xylitol likes to harden quickly.
Place in the fridge to speed up the drying process. It may take anywhere between 24-48 hours to harden, depending on the depth and size of the molds. Pop them out of the silicone molds when the liquid has dried and changed to a lighter color.
Keep in an airtight container as xylitol likes to pick up moisture from the air.
Notes
Consuming more than 20g of xylitol per day may have negative gastrointestinal effects.
Keep xylitol away from pets, especially dogs and cats as it is poisonous to them.