Firstly, I'd like to thank Stanley, Rochelle, Amy, and Windy for their comments and recommendations. We were certainly more than pleased with the dinner we had there earlier this evening.
Stanley did a fabulous job describing the food, and I have a little to add.
We knew that we were in good hands when the excellent French bread arrived nice and warm and crusty. The caulifower soup with truffle oil was superb--the flavor of caulifower and truffle essence playing off each other in a silken puree. I had the foie gras ballotine with brioche and prunes, and that was a very special indulgence, indeed, even if it added only $1.50 to the price of the $35 set menu. The scallop with rice pilaf was good, but not as remarkable as the preceding or following courses. The magret of duck was excellent: skin crisp, meat served rosy, juicy, and of a velvety tenderness. Although I usually ignore polenta, I made quick work of Chapeau's truffle-scented version.
I also must confess to cadging a couple of morsels of my husband's cassoulet. I was rewarded with one of the best versions I've tried anywhere--France included. The beans were meltingly tender, and so very flavorful I dread to imagine the duck and pork fat that went into that dish. (Of course, the generous amount of garlic may be considered a mitigating circumstance.)
At the end, it was pure "gourmandise" (a diplomatic French word for greed) that kept me going through the molten-centered Valhrona chocolate cake with rum raisin ice cream and caramel sauce. I'm sure I would have enjoyed it more had I not eaten so much beforehand. (An excellent thali lunch at Dasaprakash did not help.)
The wines were very good value for money. And the half-glass concept an excellent idea. The only downside was the noise, which made conversation rather difficult, although we were seated very close together at a smallish table. Perhaps I ought to return on a weeknight.
I would certainly hurry back to Chapeau!, and I can only join Stanley in wishing that there were more places like it in San Francisco.