Butter lettuce is the measure of a cook's patience. It cannot be rushed or hidden. If the heads are tired, or if they sat too long after harvest, no amount of dressing will save them. But when you find butter lettuce at the market with that perfect softness, leaves that yield like silk and taste faintly sweet with a gentle mineral finish, you have something worth protecting.

The French understand this. In Paris, a proper green salad is not an afterthought. It arrives after the main course, a few perfect leaves dressed at the last possible moment. The vinaigrette is restrained. The point is the lettuce itself.

Here, crème fraîche enters the dressing and changes everything. It rounds the vinegar's sharpness and clings to the leaves in a way oil alone cannot. The herbs should be soft ones: chervil with its faint anise, tarragon with its licorice bite, chives for a whisper of onion. These are the herbs that belong beside delicate things. Let things taste of what they are.