What should I cook from level 90 cooking to level 99 cooking? Preferably the fastest things possible.

Monkfish then sharks :)

When I did 99 Cooking, it was alot cheaper than it is now and I still ended up spending around 10m doing sharks from 80-somthing :P

Good luck!

Monks to 92-94, sharks to 95, rocktails to 99.

 

The burnrate on sharks starting from 92 is not all that high, you might want to consider starting them earlier than 94. Shouldn't make much of a difference either way.

i did monks from 90-93 sharks 93-95 rocks 95-97 sharks 97-99

 

 

from 93-94 sharks, i only burnt 26 so its 100% worth it, and be careful about rocks, just because the g/e says profit, dont mean it always is

Honestly id just go shark the whole way. If you have gauntlets you wont burn much at all and you wont have to think at all haha.

if you value your time over 150k gp/hr, then sharks to 95, rocktail to 99

if you value it over 1.5m/hr, make wines instead.