To make the blini:
Cook the potatoes in a pot of salted water, cooking for about 20 minutes or until just done. Put the cooked potatoes through a ricer and reserve.

Add the flour and baking powder and mix well with a fork. Slowly add the milk and butter. Incorporate the 2 eggs and season with salt and pepper. The batter should resemble a pancake batter.

Heat a well-seasoned or non-stick pan until warm over medium heat. Carefully ladle into the pan 2-dollar size mounds of batter. Cook on one side and then flip over to brown the other side. Repeat this process until you have used all the batter. Reserve in a warm place.

To clarify the butter:
Gently warm the butter. As it warms, foam will accumulate on the surface. With a thin metal spoon, skim this foam away into a container. (Save the foam to spread on your morning toast, it's lower in fat than regular butter and just as tasty.) Carefully pour off the clarified butter into another pot, leaving behind the milky water on the bottom.

Assembly:
Place a potato blin in the center of each serving plate. Spoon 2 tablespoons of the crème fraiche on the blini. Place a teaspoon of the caviar on the crème fraiche. Top with another blin and repeat the process until all is used. This will look like a stack of pancakes topped with crème fraiche and caviar.

Drizzle 2 tablespoons of the butter around the stack. Scatter the chives and red onions around each plate. Serve immediately.