First of all I didn't pour grease directly down the drain, I assume over time cleaning plates that had small amounts of grease on them built up over time.
I wouldn't say the drain was clogged, rather I think the p-trap wasn't tight enough and it came off, causing water to come out. While I was checking it out I noticed all of the grease and did what I could to clean it out of the p-trap and the other accessible pipe.
What's the best way to clean out any grease I assume is further down the pipe that I can't easily access? The sink still drains perfectly fine so I doubt it's much, it probably mostly got caught in the p-trap.