Preheat oven to 400 degrees. Butter 20 muffin cups generously with 2 1/2 Tbsp of the melted butter. Dust muffin cups with flour then shake out excess, set aside. In a blender combine milk, eggs, flour, salt, vanilla, and remaining 2 Tbsp melted butter and blend until well combined, about 10 seconds. Fill prepared muffin cups about half way with batter . Bake in preheated oven 14 - 17 minutes until puffed and golden . Run a knife around edges to loosen . Serve warm with desired toppings.
