Liquid Cake Shortening

Check out amazon you will find suppliers there

High-ratio shortening is only available commercially. It's almost impossible to find in retail quantities.

I'm guessing the recipe calls for an oil ,rather than butter, so you might try a neutral oil like canola or a room temperature coconut oil . Let us know how your cake turned out. Neither of these will clash with any other flavors in your cake, so you should be fine.