01 - Preheat the oven to 350°F. Grease a 24-cup mini muffin tin thoroughly or line with paper liners.
02 - In a large mixing bowl, whisk together the flour, sugar, baking powder, baking soda, salt, and ground cinnamon until well combined.
03 - In a separate bowl, whisk together the milk, vegetable oil, egg, and vanilla extract until smooth and fully incorporated.
04 - Pour the wet ingredients into the dry ingredients. Mix gently with a spatula or wooden spoon until just combined. The batter should remain slightly lumpy—avoid overmixing to prevent tough muffins.
05 - Divide the batter evenly among the prepared muffin cups, filling each about ¾ full. Use a spoon or cookie scoop for consistent portioning.
06 - Bake for 10–12 minutes, or until a toothpick inserted into the center of a muffin comes out clean. The tops should be lightly golden.
07 - Allow the muffins to cool in the pan for 5 minutes, then carefully transfer to a wire cooling rack.
08 - While the muffins are still warm, dip the tops in melted butter, then immediately roll in the cinnamon sugar mixture to coat evenly.
09 - Serve warm or at room temperature. Best enjoyed fresh on the day of baking.