Place potatoes in a large saucepan. Cover with at least 2 inches of cold water and place over high heat. Bring to a boil, then reduce heat to a simmer and cook until tender, about 20-30 minutes.

Heat a non-stick griddle to 350°F.

Peel potatoes and press through a tamis, or a very fine mesh sieve. Immediately weigh out 9 ounces (250 g) into a medium bowl.

Add flour and whisk into potatoes. Add crème fraîche and whisk in. Add one egg and whisk in. Add second egg and whisk in. Add egg yolk and whisk in. Check batter for proper consistency by letting batter drizzle from the whisk. It should hold its shape as it hits the batter. If needed, add a bit more crème fraîche and whisk in. Season to taste with salt and pepper.

For each blini, spoon about 1 1/2 tsp batter onto griddle and cook about 1-2 minutes per side. Serve immediately, if possible, or keep warm in a low oven while cooking remaining blini.