Agar-agar. It looks like gelatin and acts like gelatin, but it's definitely not gelatin. Agar is the vegetarian-friendly version of gelatin, with no animal collagen. It's a plant-based thickening agent you can use in desserts and soups in lieu of the more popular gelatin. Jeff Potter shows us what he can do with orange juice, sugar, agar powder and a touch of rum, for a great screwdriver jelly.