Don’t know about California – I’m in Florida, but the following may be helpful as some general guidelines to help you find the answers that would be specific to California.
Here, in Florida, most items sold under cottage-food law would NOT be taxable, but CANDY is ALWAYS taxable. Thus, bread, cookies, cakes, muffins, etc. would not be taxed but caramels, fudge, chocolates, etc. would be taxed.
There is also one more thing to consider: does the venue where you are selling charge admissions for customers to enter? If so, then items that are big enough or packaged for taking away from the venue are not taxable. Things that are sold to be eaten on the premises, however, are taxable. Thus, if you sell a blueberry muffin at a regular farmers market, it wouldn’t be taxed, but if you sold it at a fair where the customer had to buy a ticket to get in, then it would be taxed.
I hope that helps you at least somewhat, but do check with whoever oversees California’s cottage-food laws (perhaps Department of Agriculture) AND California’s sales-tax laws (perhaps department of revenue), since California’s laws are often vastly different from those of any other state.