Chantilly is a method which is applied to cream of course, but also to other surprising ingredients.
If we look at the more scientific side of Chantilly we can see that it's mainly cream, and cream is a mix of very small droplets of milk fat and water, which is called an emulsion. When we whip this emulsion, we incorporate air into it and so create a mousse or foam. In the end Chantilly is a foaming emulsion.
The interest of this observation is that we can imagine doing the same not only with cream. We just need water and fat. And it works, so you can make foie gras Chantilly.
This is not foie gras with Chantilly (yuk!) but foie gras whipped to a foam like a Chantilly, but without cream added.