This is video is outdated since it doesn't include one advanced technique after using an item with the red hot fire. See the updated video for a slightly faster run.

After getting all the ingredients just like in the cereals first route, instead of scrolling the inventory to the top, scroll so the cereal appear at the bottom. Then, when going to the kitchen, click on the cooking pot so Guybrush starts walking, use cereal with cooking pot, then type "U", click on the cooking pot, and scroll the inventory up as much as you can before Guybrush gets to the cooking pot. The timing is tricky, but if you manage to do it right, you won't have to scroll the inventory during the rest of the process, which saves between 3 and 5 tenths of a second.

Shout-outs to frozenspade for finding out about this advanced scrolling technique.