Vichyssoise (leek and potato soup) with Melba toast

For the leeks, cut off the root end, remove the outer leaves and the dark green tops; cut where the light green stem meets the dark leaves.

Soak the leeks in warm water several times until the water runs clear; drain root side up.

Chop the light green stems for the soup; save the trimmings for the chicken stock.

Crack chicken backs, wings, feet and necks for the stock; add white wine with the stock vegetables and herbs. Do not move the pot while it cooks, or the stock clouds.

Peel the potatoes and cut into chunks. Melt butter in a large saucepan.

Sweat the leeks in the butter for 7 minutes without colour.

Add gray salt, the potatoes and the chicken stock; cover and cook on low heat about 30 minutes.

Turn off the heat, uncover and let sit 10 minutes.

Transfer to a high-powered blender, holding back about 30% of the liquid; add more if needed.

Add sour cream or heavy cream and a drizzle of olive oil; blend with the center cap out and a folded towel on top so steam escapes.

Strain through a fine sieve. Serve hot or chilled.

For the Melba toast, cut rounds from French sandwich bread and slice them very thin.

Brush the bread with melted butter on both sides, sandwich between parchment and baking trays, and toast in the oven.

Grate Parmigiano Reggiano and black truffle over the toasts; serve as the garnish.