I've had occasion recently to be in Sonoma during the week and have tried a few of the places for lunch, including the chowhound-known ones of Basque Boulangerie and Taste of The Himalayas (both were as advertised, quite good). But my favorite has turned out to be the Sunflower Cafe (they may spell it "Caffe"), the latest incarnation of 421 First St. West (on the west side of the square) in the building said to be once occupied by General Vallejo. You order at the counter, pay, take a number, go to your table, and they bring your food to you. That doesn't give a sense of the high quality of the food I and others had there, sandwiches, soups, and salads. I'd call everything a "cut above" including the small green salad that's served with all sandwiches, the very attractive plates and trays, and the great patio in the back with tables and umbrellas. Also the very friendly and attentive people who work there. This place is run by people who know about quality and service in a deli-style setting.