For the Basic Buckwheat Crepes:
By hand: Place the flour and salt in a bowl, add 1 cup water, and stir with a wooden spoon or your hand until smooth and stiff. Add more water, stirring, until you have a batter with the consistency of mayonnaise. Beat for 10 minutes.
Using a stand mixer or a food processor: Place the flour, salt, and water in the bowl and mix or process for 5 minutes.
Cover the batter while you heat two griddles or heavy skillets over medium-high heat. Wipe the cooking surfaces with a lightly oiled paper towel or cotton cloth.
Scoop up 2 to 3 tablespoons batter and dribble it in a spiral on one griddle, then immediately spread it from the center outward, using the back of a large ladle or an offset spatula. (Your first few crepes will be a little thick and uneven as you experiment with temperature and quantity and as you work out a system for spreading the batter.) Cook the first side for about 1 minute, then flip the crepe onto the other griddle and cook until set, about 1 minute. Put a little butter on top and, when it melts, fold the crepe in half and serve it. Repeat with the remaining batter.
For the Modern Crepes:
By hand: Place the flours and salt in a bowl and mix well. Add the egg and 1 cup water and mix with a wooden spoon or your hand until a smooth, stiff dough forms. Add more water, stirring, until you have a smooth batter; do not beat.
Using a stand mixer or a food processor: Combine the flours, salt, egg, and water in the bowl and mix or process to a smooth batter. Heat two griddles and cook the crepes as directed above.
Once you’ve flipped the crepe over, you can break an egg onto it in the center. Use a fork to scramble it, or just spread the white. Top with a little butter and season with salt and pepper. Cook until the egg sets, then fold the four edges over to cover the egg. Serve with a little pat of butter on top.