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.

Then, after burning an item using the red hot fire, you can use the one item with the pot and quickly buffer a second action in order to use another item immediately. This also saves between 3 and 5 tenths of a second.

Shout-outs to frozenspade for finding out about the advanced scrolling technique and to hyperformance for showing how you can buffer an action after using the red hot fire.