1. Place potatoes in a medium saucepan and add enough cold water to cover by at least 2 inches. Bring to a boil over high heat; reduce heat to a simmer and simmer until potatoes are tender and easily pierced with the tip of a knife.

2. Drain and peel warm potatoes; press through a very fine mesh sieve. Immediately weigh out 9 ounces pureed potatoes and transfer to a medium bowl. Working quickly, whisk in flour and 2 tablespoons creme fraiche. Add 1 egg, whisking until batter is smooth. Add second egg, whisking until batter is smooth. Finally add the yolk; whisk until batter is smooth and well combined.

3. Hold the whisk with some of the batter over the bowl. The batter should fall in a thick stream but hold its shape when it hits the batter in the bowl. If it is too thick, add a little more creme fraiche. Season with salt and pepper.

4. Heat an electric griddle to 350 degrees or a large nonstick skillet over medium-low heat. Working in batches and wiping griddle with a paper towel between each batch, spoon 1 to 1 1/2 teaspoons batter onto griddle or skillet for each pancake. Cook until bottoms are browned, 1 to 2 minutes. Turn and cook on second side until evenly browned with a small ring of white around the edges, about 1 minute. Transfer to a small baking sheet and keep warm. Serve immediately topped as desired.