For the caramel, add sugar to a medium pot on medium heat and cook sugar until it melts and turns amber in color. Approximately 10-12 minutes. (340-345F if using a candy thermometer). Remove from heat and quickly whisk in vegan butter. Be careful this mixture is very hot!
Pour the caramel in to the bottom of the flan dish and set aside. Fill caramel pot with water and bring to a boil with caramel cooking utensil for easy clean up, he boiling water will dissolve the hardened caramel.
In a large bowl whisk together all flan ingredients until thoroughly combined. Transfer mixture into pot and bring to a boil on medium to medium-high heat. Be sure that you continually whisk and keep a watchful eye that mixture does not boil over and out the pot.
After 5 minutes of cooking pull from heat and allow to cool slightly. Pour hot mixture over top caramel and allow to cool down to room temperature before refrigerating.*If you do boil the mixture for at least 5 minutes, the agar will not re-hydrate and be able to set your flan.
Refrigerate 4 to six hours or until flan has reached 39-40F internal temperature.
Gently loosen edges of flan from the sides of the dish. Flip onto a large plate and serve.