I bet she is a great baker.

Applejack IS a great baker.

We've seen her cook before in the show... Most of her pastries would be made out of apple, though.. Which is good! xD

The only time Applejack's baking was bad was when she was out of it after bucking trees all day and made everypony sick.

^ In Apple Family Reunion, we saw her make Apple Fritters. Oh, and in A Canterlot Wedding she made Apple Cupcakes. :D So that counts as something.

I can actually see this happening. Don't know if I'm right, it's just a...feeling!

After seeing Applebucking season, I know AJ will get everything under control.

Honestly, I don't think I'd be interested in a particularly reliable character substituting and doing a great job of it. I love Applejack but I think she'd just be responsible and do everything right, which would be boring. XD

I think Spike would have the potential to do a great job (after all, he is shown to love baking) but after he's just become confident that everything' going fine, something will happen. Like he'll eat all of a certain ingredient and then use a substitute that doesn't work out. Or he'll get distracted and forget he's put a batch of cakes in the oven. Or, instead of forgetting he's got something in the oven, he'll just lock himself outside by accident!

Maybe during this time, Twilight would stop by to check on him a couple of times (skeptical about his abilities to handle it all) and he would have to cover up all his problems, pretending everything's going just fine. It'd possibly end with both Pinkie and Twilight convinced that Spike did everything perfectly, but then Spike finally admitting to all the problems he had and/or getting found out by the two when a cake explodes or something. The lesson he learns might be a cross between Fluttershy's "don't bite off more than you can chew" and Applejack's "it's okay to let your friends help you" lessons from the first season.

Spike definitely has the enthusiasm for the job, but I think he also have just enough lack of responsibility for this sort of storyline to be pretty entertaining. :)

^ Huh, good point. That WOULD be entertaining!