It is no different from trying to other deleted files, you need to use one of the file recovery software applications. Try a google search for that term and see what that brings.
The file is still present, the actual file name is removed from the file table listing and the space is marked as free, so it can be reused. The sooner you try to recover the file, the more chance of success, the longer you leave it the greater the chance of that space being overwritten and the file is truly gone.
Avast doesn't delete by default it sends to the chest, so if you have selected delete, that is exactly what avast does, the file is deleted. A copy isn't saved anywhere and it isn't sent to the normal recycle bin for obvious reasons it would be detected again there.