In a large bowl, whisk together the spelt flour, buckwheat flour, and a pinch of salt.
In a separate bowl or jug, whisk the eggs and milk together until smooth.
Pour the wet mixture into the dry ingredients, whisking gradually to form a smooth batter.
Slowly add the water, whisking until fully incorporated. The batter should be thin and pourable, like heavy cream.
Cover and rest for 30 minutes at room temperature, or refrigerate for up to overnight.
To make the mushroom duxelles, melt the butter over medium heat in a large frypan. Add the shallot and garlic, and cook for 1–2 minutes until softened and fragrant.
Add the mushrooms and thyme, and cook for 10–12 minutes, stirring frequently, until the mushrooms release their moisture.
Add a splash of white wine, if using, and cook until fully absorbed. Alternatively add a little water or more butter to the pan if needed.
Stir in the crème fraîche or cream, and season well with salt flakes and black pepper. Cook for another minute until thick and creamy. Set aside.
To cook the crepe batter, heat a non-stick crêpe pan over medium heat and lightly grease with butter.
Pour in about ¼ - 1/2 cup of batter, swirling to coat the pan evenly.
Cook for 1–2 minutes until the edges lift and the bottom is golden. Flip and cook for 30 seconds to 1 minute on the other side.
Stack on a plate and cover with a towel to keep warm. Repeat with remaining batter.
Preheat the oven to 180°C if you’d like to serve them hot and melty.
Spoon some mushroom duxelles onto one half of each crêpe and top with grated Gruyère AOP.
Fold the crêpes in half, then into quarters, or roll them.
Arrange on a baking tray or ceramic dish and warm in the oven for 5–8 minutes, or until the cheese is melted.
Serve warm, optionally with a lightly dressed green salad or fresh herbs like chervil tarragon or parsley.
As buckwheat and spelt flour absorb moisture differently, it’s always best to gradually add liquid to batter, it should be a thin, pourable consistency, not too thick or too watery/runny.
4 servings