Also in CA - Yuba County, and no, you can't run a food service business out of your home in the WHOLE state. It stinks, I know. You would need to find a certified kitchen in which to bake. Some towns have kitchen space you can rent out, that is the landlord's business, or talk to a local restaurant that may be closed certain hours of the day, and you could use their kitchen in their off hours. You will also need to get a federal food handler's certificate. My husband and I both have ours. Basically, you go to a one day class, take the test after, and within a month, you are certified.
Sometimes church kitchens are available, or maybe your child's school will work with you, although liability is an issue. You will also need a permit from your county's environmental services department - or whatever county you are going to sell in. You will need liability insurance - we carry a $1 million policy - it's about $1,000 a year, but without it, you cannot work farmers' markets or street fairs.
My husband and I have owned our own business for almost 8 years, and that is how we do it.