Reiterated...YOU are the owner.
It's not unusual for a chef to jump ship when a new owner comes in. He/she has been used to doing things "as they liked" because there was either an uninterested party at the checkbook or because the chef strongarmed the previous owner.
If you purchased a restaurant to flex your own culinary muscle by menu designing, developing specials, experimenting with breads and desserts, etc., then this chef must understand you sign the checks AND the walking papers. (Keep in mind, I saw 30 responses to this thread, haven't read them all and this may very well be a moot point.)
This person must understand, he is an employee. Yes, you want to show a chef respect, you want to accept input, etc. but YOU as the owner must be satisfied. Sounds to me like some new life needs to be breathed into your establishment. Start interviewing new chefs NOW if the present one doesn't want to march in formation.