We've been to Croatia a number of times now, from Dubrovnik to Zagreb, and Konoba Ranc Tučepi is our favourite restaurant.
Fantastic authentic Croatian food, just as my mum would cook it at home (I'm from Croatian decent). Great selection on wine and service is nice too. Kid friendly.
You won't find a more beautiful setting for a restaurant in the country.
I'd recommend you book in advance during July/August.