Preheat your oven to 350°F (175°C) and line a mini muffin tin with paper liners.

In a large mixing bowl, combine the flour, sugar, baking powder, salt, and ground cinnamon. Whisk together until well blended.

In a separate bowl, whisk together the milk, eggs, melted butter, and vanilla extract.

Pour the wet mixture into the dry ingredients and gently fold them together until just combined.

Spoon the batter into the prepared mini muffin tin, filling each cup about two-thirds full.

Bake in the preheated oven for about 12-15 minutes or until golden brown. A toothpick inserted into the center should come out clean.

While the doughnut bites are baking, mix together the granulated sugar and ground cinnamon in a small bowl.

Once the doughnut bites have cooled for a few minutes, gently toss them in the cinnamon sugar mixture until well coated.