Alright, I'll start off by saying baking and cooking are not the same thing, just cause you can do one does not mean you can do the other. I would like for there to be some sort of baking skill and I'm calling it a pastry skill just cause that flows a bit nicer so here's my ideas on it.
For starters this skill would add new flavors and plants.
Vanilla (In an extract to be purchased from the store)
Caramel (In a bottle to be purchased from the store)
Chocolate (In the form of cocoa powder to be purchased from the store)
Peanut Butter (Jar)
Now this skill could have the opportunity to for some customization. Of course when your begin at level one you can only make simpler deserts like cookies. As you progress through the levels you gain the ability to make pies, fruit tarts, doughnuts, and cakes. Cakes would become much more complex upon mastering the skill.
As for customizing a creation it could work like this you click on your Sims fridge/stove and the option "serve deserts (now modified)" will come up you then choose the type of desert (pie, cookie, cake etc) then the flavor you'd like to use, eventually you'll be able to combine two together.
So in example you click the fridge/stove and select pie then say for a flavor you select blackberry.
In example for higher skill Sims after selecting type of desert (in our example its cake) you will choose to use either one or two flavors for this cake. Higher skill Sims will be able to bake cakes with up to 3 tiers.
Now with the case of doughnuts there would be the need to add a new item, a deep fryer which could of course be used in other non desert recipes.
Another new item that would fir in with this skill would a "pastry decorating machine" This could be used to add sprinkles to cookies, powder/cinnamon to doughnuts, a garnish to a pie and would be a lot of fun for cakes. After baking your cake you could use the machine to select a frosting, decorations and possibly a topper. Sims that have mastered the skill would have access to toppers for wedding/birthday cakes and be able to use their tasty creations for those actual occasions.
As suggested by Coffefreak4Life, HazzaPlumbob
There could also be different types of breads added using this skill such as raisin bread, Baguettes, Sourdough, braided coffee cake, Pumpkin loaf etc.
As suggested by A deep fryer would add lots of other food items
such as French Fries, Funnel Cakes, etc
So anyone else want a Pastry/Baking skill please sign!!!
And Thank You
A List acknowledging all those in support (171 signatures so far)