Caviar Eggs

Open and sterilize eggshells: Carefully remove top third of each eggshell by tapping around egg with a paring knife, then gently pry off top and discard. Pour eggs into a bowl, reserving shells. Use a knife to tear any membrane remaining in bottom of eggshells. Generously cover shells with cold water in a 3-qt saucepan and add vinegar. Simmer over medium heat, gently stirring occasionally and skimming off any foam, 15 minutes. Carefully transfer shells with a slotted spoon to a rack to cool. Gently wipe shells inside and out with a damp paper towel to clean completely. 3Put eggshells in eggcups or small glasses to keep them upright. Whip cream and scramble eggs: Beat cream with a whisk until it just holds stiff peaks, then beat in lemon juice, vodka, 1/4 teaspoon salt, and 1/8 teaspoon cayenne. Lightly beat eggs with a fork, then add 1 1/2 tablespoons butter, 1/8 teaspoon salt, and remaining pinch of cayenne. Melt remaining tsp butter in nonstick skillet over medium heat, then cook egg mixture, stirring constantly, until eggs are just scrambled, 3 to 5 minutes. Divide among shells and top with whipped cream and caviar.