Preheat your oven to 400°F (200°C) and place your muffin tin inside to heat.

Combine the all-purpose flour, milk, eggs, sugar, vanilla extract, and salt in a blender and blend until smooth, about 30 seconds.

Remove the hot muffin tin, add ½ tablespoon of butter to each cup, and swirl to coat.

Pour the batter into each muffin cup, filling them about ¾ full.

Bake for 15-20 minutes until puffed and golden brown.

Let cool for a minute, then remove from the tin and serve warm with toppings of your choice.