For the cupcakes: Preheat the oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners.

In a medium bowl, whisk together the flour, baking powder, cinnamon, and salt.

In a large bowl, cream the butter and sugar together using an electric mixer until light and fluffy, about 3 minutes.

Add the eggs, one at a time, beating well after each addition. Stir in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Mix until just combined.

Divide the batter evenly among the 12 cupcake liners, filling each about two-thirds full.

Bake for 18–20 minutes, or until a toothpick inserted into the center of a cupcake comes out clean. Let the cupcakes cool in the pan for 5 minutes before transferring to a wire rack to cool completely.

For the cinnamon sugar coating: In a small bowl, mix together the granulated sugar and cinnamon. Brush the tops of the cooled cupcakes with the melted butter, then roll them in the cinnamon sugar mixture to coat.

For the chocolate ganache: In a small saucepan, heat the heavy cream over medium heat until it begins to simmer. Remove from heat and add the chopped chocolate. Stir until smooth and glossy.

Drizzle the chocolate ganache over the top of each churro cupcake.

Let the ganache set for a few minutes before serving.