Both of these are similar in some ways where you are mixing ingredients to come up with something else.
Could you introduce something like a tool that allows people with Alchemy and cooking skills to create specialized items.
For example, using this tools if the players had cooking and alchemy skills they could create a compound that magically repaired or temporarily enhanced specific items. Unguents that raised bonded pets. Potions to cause weapon skill like effects when thrown at a target. (Bleed, paralyze, mortal blow, etc..)
Because these things could only be created from a specific tool and this tool required cooking and alchemy, the skills would be useful.
