How do i use Query Posts as a widget?

I want to create a widget with the last post from a user.
It should look like this:

POST TITLE
Excerpt […]

And i need to link the post title as a permalink to the post.
I’ll also be manually adding a user thumbnail linking to the user’s posts and widget title manually.

I might need to use this widget more than once, for different users.

Can someone please provide me with the php code please?
If user filter is not possible, a tag or category filter could also do.

Thanks a lot in advance!