I found the fiber paste at Michael's and thought it would work better than gesso. It's much thicker than gesso, and it was really great for this technique...dried quickly and it easy to work with. But you could certainly try gesso or any of the other types of paste they have in stock - molding paste, dimensional paste, etc.! (Use a coupon if you get it at Michael's - the Fiber Paste is around $16 if you don't use one.)
In the video, I'll also show you how to color your paste to match your cardstock, so you can do this technique with any color.