Food mess

I was somewhat amused by the stain left on the oven dish that we couldn't get rid of (yet!). So I took the chance to take some photos of it. I know, i must be a bit gross right :p Just experimenting, this could be ending in a horrible mess! :S 

I struggled to get everything in focus, I mostly tried to keep the ISO at 125 to highest of 200. And I have tried to play by adjust F-stop and shutter speed. I'm using a 19-pt auto-focus. What will be the best way to take macro with even focus rather than blurred in regions out of the focus point? i.e. higher F-stop? Thanks! :)