Place the eggs, milk, water, vanilla extract, sugar, melted butter, and flour in the jar of your blender and blend until smooth. If you want to make savory crepes, avoid the sugar and vanilla extract.
Place the batter in a bowl, cover with plastic wrap, and refrigerate at least 1 hour to overnight.
Heat a small (about 8-inch) pan over medium heat. Add butter or cooking spray to coat. Pour about 3 tbsp (¾ of a ¼ measuring cup) into the center of the hot pan and swirl to spread the batter evenly.
Cook for about 30 seconds and flip it. Cook the other side for about 10 seconds more and transfer to a cutting board or clean counter. Do not stack them until they cool down. Once the cool down, you can stack them without them sticking to each other.
Continue with the rest of the batter.