Preheat the oven to 350°F.
In a bowl, add the flour, baking powder, salt, and cinnamon. Mix and set aside.
In another bowl, add the melted butter and sugar. Cream together for 1–2 minutes.
Add the egg, milk, and vanilla extract. Mix until combined.
Gradually combine the dry ingredients with the wet mixture.
Line a muffin or cupcake pan with liners.
Evenly divide the batter into each liner. (Using a cookie scoop helps keep them uniform.)
Bake at 350°F for 20–22 minutes, or until a knife or toothpick inserted comes out clean.
Melt the butter in a microwave-safe bowl and set aside.
In a separate bowl, mix the cinnamon and sugar.
Once the muffins are done, let them cool for 10–20 minutes.
After cooling, dip each muffin in the melted butter, then coat in the cinnamon sugar. Repeat for each muffin.
Peel back the liner and enjoy
