Scrub potatoes well. Boil until soft, but not mushy. Drain and cool.
Slice each potato in half. Using a melon baller or sharp-edged spoon, remove a semi-sphere of flesh, leaving a small bowl of potato. Discard the.
Removed portion. Fill with tapenade. In a small flat dish, mix just a touch of olive oil with the walnuts. Use your finger or a small basting brush to lightly cover the potato skin with oil as well. Roll the truffle in the crushed nuts to coat.
In a small bowl mix radish slices, soy sauce, rice vinegar, and garlic. In a small, heat-proof bowl or pan, sprinkle gelatin over milk. When the gelatin is hydrated, heat it gently, stirring, until all the powder is dissolved. Remove from heat, cool slightly, and stir in yoghurt. Drain radishes. Into a deep candy mold or ice tray, pour in a small amount of the yoghurt-gelatin mixture, then layer a few radish slices with two or three peas, careful to leave room for the yoghurt-gelatin to surround the vegetables for a smooth-surfaced truffle. Finish with a large radish slice for the base. Chill several hours until firm. Gently remove from mold.
Strawberry Shrimp Chipotle:.
Peel eggs. Slice crosswise, about 1/2 inch thick. Separate the white and yolk, setting aside the white for now.
Place the shrimp in a small bowl. Drain chipotles onto the shrimp.
Slice chipotles crosswise in 1/2 inch slices, removing any seeds.
Clean strawberries, removing stems and any hard, white parts. Mash with egg yolks. Construct the truffle by choosing a slice of egg white for the base. Place two or three drained shrimp on top of the egg white. With a small spatula, cover smoothly with strawberry mixture. Garnish with a chipotle skirt or crown .
Arrange a personalized assortment for each guest on a small chilled plate. Serve cooler than room temperature, but not so cold that the flavor is lost.