What is the type of bathroom faucet that mounts from the top?

I have a sink where the original owner remodeled into a tight space. Now I need to replace the widespread faucet and am having troubles finding the correct mounting type. Because of the tight space, the cabinet is under-sized for the sink so the sink bowl interferes slightly with the holes so a traditional faucet that tightens from underneath the deck is generally impossible. The sink that I removed had a large nut at the bottom of the deck but mounted from the top of the sink. I cannot find someone who knows the name of this type of faucet mount.

What type of faucet would I be looking for that mounts from the top like this?

I’ve added a picture from underneath the sink to describe what it looks like.