Combine gelatin and water. Stir gently to ensure all gelatin is submersed completely. Let stand for 5 minutes or until thick. Should be springy to the touch.
In a double broiler, melt gelatin mixture into a liquid.
Add corn syrup and oil, mix well.
Stir in butter and remove from stove just before the butter is completely melted.
Stir in vanilla and mix well. Let mixture cool to a lukewarm texture.
In a large bowl, place half of the confectioner's sugar and make a well in the center.
Pour gelatin mixture into the well and mix until combine. (I used a mixer with the dough hook attachment for this step but it can be done by hand).
Slowly add more confectioner's sugar (about 1/2 of a cup at a time). Let fully incorporate and test if the fondant is sticky to the touch. Continue adding sugar until the stickiness has disappeared.
Knead for about 5 minutes or until the fondant has come together. (I think it feels like playdough)
If the mixture is too wet, add more confectioners sugar. If the mixture is too dry add water one drop at a time.