I'm sure most of us have something like this, but here is our version.
The braces make it sturdy and keep it from shifting. The notch at the top is for the faucet. When we get where we are going we have a plastic vertical drawer stack we use like a dresser that goes on there (among other things).
WARNING: If you're a big person you better sand it smooth or you could end up with a splinter in your left cheek.