Preheat your oven to 350°F (175°C).
Lightly grease your mini muffin tin or line it with muffin liners.
In a large bowl, whisk together the flour, baking powder, salt, and 1 1/2 teaspoons of cinnamon.
In another bowl, beat the eggs, then add the milk, melted butter, brown sugar, and vanilla extract. Whisk until combined.
Pour the wet mixture into the bowl with the dry ingredients. Stir gently until just combined.
Fill each muffin cup about 2/3 full with batter.
In a small bowl, mix together the granulated sugar and 1 teaspoon of cinnamon for the topping.
Sprinkle a little of the cinnamon-sugar mixture over each muffin before placing them in the oven.
Bake for about 12-15 minutes or until golden brown.
Allow the muffins to cool in the tin for a few minutes before transferring them to a cooling rack.