My wife and I had brunch at Cafe at Ch. Souverain last Sunday.
Very good service, professional and friendly staff.
The restaurant provides excellent view of the estate vineyard with what appear to be some outdoor seating that I assumed are available during the milder/warmer/drier days.
We started with a good cheese plate for appetizer. The cheeses were mostly local (Sonoma and Marin) plus one French.
For entrees, the poached egg on crab cake was one of the better version I've had. My wife's French Toast was fine, but there were some burned spots which we were not sure if done intentionally or not.
Each item on the menu included a suggested wine pairing (all home brand).
Overall, we were satisfied with the food quality but found the brunch item prices a bit on the high side. Only because we feel that there are comaparable brunch available in SF and Marin (where we live) for lesser price and shorter distance. I would recommend it if one were in the area.
One other positive note is 20% discount for diners at the wine store.