Ideas for plugging a hole in granite vanity
Find a sink that you like with a slightly larger dimension and cut the granite to fit. With the right tools it's very easy and obviously you need to be careful. The only expensive item you need is a grinder. The others are a big sponge, bucket, diamond grinder wheel and water. It's a bit messy so I'd do it outside.

1 get your sink. 

2 confirm that it is suitable.

3 measure and mark by scratching in the surface of the granite 

4 on a flat surface shimed up for blade clearance, grinder in hand and sponge in the other. Wet soak the sponge and use it to keep the blade wet as you grind. (if you get help a hose will work)

Cut in from the opening to the line all around then cut on the line to knock off the pieces.



5 check for fit, trim if necessary and clean up. 

I've done this before and it took about 20 minutes to do the actual cutting. I'm sure you can find videos online.