Sift together flour, baking powder, baking soda, salt, and sugar into a large mixing bowl.
In a separate bowl, whisk together the egg, vanilla, milk, and the cooled unsalted butter until combined.
Pour the wet ingredients into the dry ingredients and whisk just until combined. DO NOT overmix.
Heat a large skillet or griddle on medium high heat. Once hot, add 1 Tbsp of butter to grease the pan. Using a spoon or small measuring cup, pour the batter into the skillet, forming mini sized pancakes.
Cook for 1-2 minutes, looking for bubbles and firm edges. Flip and cook for another 1 minute. (Since they are mini, you want to keep an eye on them, they will cook way faster than classic pancakes.)
Once cooked, remove and repeat until the pancake batter is gone, you should have about 18-20 mini pancakes.
Serve with desired sides immediately, while still warm and enjoy.