In a blender add the buckwheat flour, water, egg, salt. Blend for 30 seconds or until smooth. If you don't have a blender, use a large mixing bowl. Add buckwheat flour, egg, salt and beat in the water gradually until a smooth batter form with no lumps.
Cover the batter and let it rest in the refrigerator for at least 2 hours, or overnight.
After 2 hours - or the next day - check the consistency of your batter and thin it out until it has the consistency of melted ice cream. I usually add up to 1/3 cup water (except for thee vegan recipe using flax egg)
Heat a lightly oiled crepes pan over medium/high heat. I use a piece of absorbent with a 1/4 teaspoon of coconut oil (or butter) on it. Rub the paper on the pan to slightly grease the pan.
Make a first crepe to test your batter consistency. Pour or scoop about 1/3 cup batter onto the pan, then tip and rotate the pan to spread batter as thinly as possible. Keep in mind that an authentic French buckwheat crepe is thicker than a regular French crepe. And it doesn't spread as well. If it's difficult to spread, add a bit more water in the batter - up to 1/3 cup. French people always discard their first crepe!
Brown on both sides about 1-2 minutes on each, store on a plate and repeat until no more batter left.
Spinach Mushroom filling
In a pan, under medium heat, warm olive oil then add the shallots. Stir for 1-2 minutes until fragrant.
Add the sliced button mushroom all at once, stir and cook for 5-8 minutes until fried on all sides until they begin to brown.
Stir in the dried oregano, nutmeg, garlic, salt and pepper if you like.
Stir in the spinach. Cover with a lid and cook until just wilted - 1 or 2 minutes.
Uncover and stir in the canned coconut cream. Simmer 2-3 minutes.
How to eat French Buckwheat crepes the French way
Butter a hot crepe pan with coconut oil, butter or vegetable oil
Place the crepes in the pan - first side you cooked on the pan. Garnish half the crepe with grated cheese, spinach mushrooms filling more cheese and close the crepe.
Cook 1-2 minutes on both sides until brown, crispy and cheese is melted.
You can omit the cheese , if you are vegan or use vegan dairy free cheese.
Make it Vegan: My husband has been vegan since May 2017, we replace the egg in this recipe with a flax egg. Simply combine 1 tablespoon of flax meal with 3 tablespoons of water. Set aside for 15 minutes. Add in the batter as an egg. We use vegan cheese or no cheese at all in the filling. The vegan recipe usually doesn't need added water after the batter sits for 2 hours in the fridge, the consistency is spreading well and the crepes hold perfectly together.