Combine all crepe batter ingredients (flour, milk, eggs, sugar (if using), salt, melted butter, and vanilla extract (if using)) into a blender.

Blend on high speed for about 20-30 seconds, or until the batter is completely smooth and no lumps remain. Scrape down the sides with a spatula if needed.

Transfer the batter to a bowl, cover it with plastic wrap, and refrigerate for at least 15 minutes, or up to 30 minutes. This resting period allows the flour to fully hydrate and the gluten to relax, resulting in more tender crepes. If time permits, an hour or two is even better.

Heat an 8-10 inch non-stick skillet over medium-low heat. Lightly grease the pan with a small amount of butter (you can use a paper towel or a brush to spread it thinly). Ensure the pan is evenly coated and hot, but not smoking.

Pour approximately 1/4 cup (or one small ladle) of batter into the center of the hot skillet. Immediately lift the pan and gently swirl it in a circular motion to evenly spread the batter into a thin, even layer across the entire bottom of the skillet.

Cook for 1-2 minutes, or until the edges begin to crisp and turn golden brown, and the surface of the crepe appears set and dry. You should see tiny bubbles forming on the top.

Carefully loosen the edges of the crepe with a thin spatula, then gently flip it over. Cook for another 30-60 seconds on the second side, until lightly golden.

Slide the cooked crepe onto a plate. Repeat with the remaining batter, lightly greasing the pan between each crepe as needed. You can stack the cooked crepes on top of each other; they won't stick.

Serve the crepes immediately with your favorite toppings such as fresh fruit, whipped cream, Nutella, jam, maple syrup, or a sprinkle of powdered sugar.