Prepare the Crepe Batter: In a blender or mixing bowl, combine the flour, eggs, milk, water, melted butter, and salt. Blend until smooth and let the batter rest for 30 minutes.
Make the Truffle Ricotta Filling: In a small bowl, mix the ricotta with truffle oil (or fresh truffle) and season with salt and pepper to taste. Set aside.
Cook the Crepes: Heat a nonstick pan over medium heat and lightly grease with butter. Pour a small amount of batter into the pan, swirling to create a thin, even layer. Cook for 1-2 minutes, then flip and cook for another 30 seconds. Repeat with the remaining batter.
Assemble the Crepes: Spread a spoonful of the truffle ricotta onto each crepe and layer with a few slices of beef pastrami. Fold the crepes into triangles or roll them into cylinders.
Plate and Serve: Arrange the crepes on a plate, garnish with fresh herbs, and drizzle with a bit of truffle oil. Serve immediately with a side of greens or enjoy on their own.