1. Blend all the ingredients for the vinaigrette in a food processor;
2. cook the lentils: boil for half an hour in unsalted water; drain and toss immediately with three-quarters of the vinaigrette;
3. place the slices of foie gras on a baking sheet and place under the broiler at its highest setting for 30 seconds on each side.

Arranging the plate

1. Place a slice of foie gras on a bed of oak leaf lettuce;
2. garnish with a spoonful of lentils;
3. sprinkle everything with the remaining vinaigrette and garnish with the chervil
4. and a few sprigs of chives.