Put the flours into a bowl, add the egg, milk, water and salt and beat to make a smooth batter. Leave to stand for 30 minutes.
Heat a little oil in a 20 cm/8 " pan and pour on a teacup of the batter, tilting the pan so it spreads evenly. Cook for about a minute, flip over with a palette knife and cook until browned. Stack the pancakes between kitchen parchment and cover with a clean tea towel to keep warm.
For the filling, heat the oil in a wide pan and cook the garlic, bacon, leeks for about 10 minutes, stirring frequently. Season with salt and pepper, remove from the heat and stir in the cheese and creme fraiche.
Place a little of the filling on each pancake and fold into triangles.