Demons didn't do sweets. They didn't eat in general, spending too much time down Below or tempting humans to sin to bother with human food. Crowley, however, was rather fond of such things.

He was of the opinion that he ought not to like sweets. His usual fare should be savory, any sweets he might consume should be of the sour variety, and his coffee should be as black as he claimed his soul to be.

In reality, the demon had a massive sweet tooth. He'd never admit it, but if he was presented with the opportunity to have something sweet, he was inclined to indulge.

So when a new bakery opened up a street away from Aziraphale's bookshop, well, he just had to check it out.