Buvette is open 18 hours a day, and people are lined up outside for most of them. That is because Jody Williams’s self-titled “gastrothèque” is not just ridiculously charming, but it also manages to hit the spot on any number of meal-period and appetite-specific levels, from steam-scrambled eggs for breakfast to a 1 a.m. croque monsieur. A common denominator on the small-plate menu is richness, a quality that extends even to the vegetables and salads. (It’s one thing to make aligot potatoes and chocolate mousse craveable; try that with carrots and beets.) Much of what you eat at Buvette is delicious things you put on bread (anchovies and butter, a signature combo) and delicious things you dip bread into (a crock of creamy mustard sauce in which assorted rabbit parts are submerged). With every detail just so — the illustrated almanac-style drinks book; the cocktail glasses chilling on the marble bar; the bistro-aproned, neck-tied servers who could conduct a master class on the art of sprezzatura — the place might feel art-directed, but the effect is transporting.