In a large bowl, whisk together the flour, sugar, and salt.

Make a well in the center of the flour mixture. Add the eggs and about half of the milk. Whisk from the center outward, gradually incorporating the flour until a thick, smooth mixture forms.

Gradually whisk in the remaining milk, water, melted butter, and vanilla. The finished batter should be very thin and pourable, similar to heavy cream. If it looks noticeably thick, whisk in 1 tablespoon (15 ml) water at a time until it reaches the right consistency.

Cover the bowl and let the batter rest at room temperature for 15 minutes. This allows the flour to hydrate and helps produce smoother, more tender crepes.

Place a 10-inch nonstick skillet over medium heat: Once hot, lightly brush the surface with a small amount of the cooking butter. The pan should be hot enough for the batter to begin setting immediately but not so hot that it browns before spreading.

Stir the batter briefly, then pour about 1/4 cup (60 ml) into the center of the skillet. Immediately lift and tilt the skillet in a circular motion so the batter spreads into a thin, even layer.

Cook for about 45 to 60 seconds: The surface should look mostly dry, the edges should begin to lift, and the underside should have light golden spots.

Slide a flexible spatula under the edge and carefully flip the crepe. Cook the second side for about 20 to 30 seconds, just until lightly golden. Do not overcook or the crepe may become brittle.

Move the cooked crepe to a plate or wire rack. Repeat with the remaining batter, adding a small amount of butter to the pan as needed. Stir the batter occasionally because flour can settle at the bottom.

If the crepes brown before the batter has fully spread, reduce the heat slightly. If they remain pale and take much longer than 1 minute to set, increase the heat slightly.

Spread each warm crepe with your chosen filling and fold into quarters or roll it into a cylinder. For plain sweet crepes, dust with powdered sugar and add berries or maple syrup.

Serve the crepes warm: For a classic sweet combination, add lemon juice and powdered sugar, fresh berries, or chocolate hazelnut spread.