Preheat oven to 400. Pulse together milk, eggs, flour, salt and vanilla in a blender until combined. Add half of the butter and pulse to combine, then add in remaining butter and pulse to combine.
Prepare 18 baking cups(muffin tins) with cooking spray. Then fill each with a scant 1/4 c. batter. Bake for 15 min. until very puffy and golden on top. Remove from oven and let sit for a few min. to deflate. Then remove and fill with your desired toppings. Can top with syrup to if desired.