In a medium bowl, whisk together flour, salt, and sugar (if using).

In another bowl, beat eggs and whisk in milk, melted butter, and vanilla (if using).

Gradually pour wet ingredients into dry, whisking until the batter is smooth and free of lumps. Let rest 10 minutes.

Heat a nonstick skillet or crepe pan over medium heat. Lightly brush with butter.

Pour about ¼ cup batter into the center of the pan and quickly swirl to coat the bottom in a thin, even layer.

Cook 1–2 minutes, until the edges lift and the underside is golden. Gently loosen with a spatula, then flip and cook an additional 30 seconds.

Transfer to a warm plate and repeat with remaining batter, brushing pan with butter between crepes.

Stack crepes with parchment paper between each to prevent sticking. Serve warm with your favorite fillings.