Preheat the oven to 375 degrees F.
Lightly brush both sides of the bread slices with olive oil, and season with salt and pepper. Place on a baking sheet and put into the oven for about 12 minutes, or until crispy on the outside and soft within. Keep warm until needed.
Turn on your espresso machine and build up the pressure.
In a saucepan, heat the cream over medium heat just until it simmers. Remove from the heat.
Break the eggs into a bowl, whisk until blended, and season with salt and pepper. Whisk in the hot cream and 1 tablespoon of the chives.
Pour 1/4 of the egg mixture into a heatproof 1-cup measuring cup (a metal pitcher for steaming milk works well). Plunge the steamer wand deep into the eggs and steam them, keeping the nozzle deep and rotating the cup to cook the eggs evenly. Don't shake the cup or the eggs will scramble. You want them to set into a cake, being careful not to overcook them. You will notice the noise changes as the eggs solidify. Lower the cup and steam the surface of the eggs. The eggs should remain soft and not be fully set.
Invert the cup onto a warm plate, top with a spoonful of caviar, and sprinkle with some of the remaining chives. Serve with 2 slices of the toasted bread. Repeat to make 4 servings.