Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).

Beat butter until softened.

Add sugar and beat until light and fluffy, about 3 minutes.

Add eggs, one at a time, beating until well combined.

Measure the flour, baking powder, and salt into a medium bowl and whisk to combine.

Measure out the milk and vanilla and stir to combine.

Scoop batter into cupcake cups about 2/3's full.

Bake cupcakes at 350 degrees Fahrenheit for about 22-25 minutes or until a cake tester comes out clean.

For the Manjar Blanco/Dulce de Leche: Boil a pot of water and immerse sealed can on its side.

Keep water at a boil for 2 hours, refreshing the water as needed.

Let cool before opening.

For the frosting: Beat butter briefly, then scrape down the bowl.

Add the milk, cinnamon, vanilla, and powdered sugar, and beat until smooth.

Add coconut and mix until combined, careful not to overmix.

To assemble cupcakes: Let them cool out of the pan for an hour.

Using a small paring knife, cut a cone out of the top of the cupcake.

Cut off the bottom of the cone, leaving behind the cupcake top.

Fill the hole with caramel.

Put the top back on the cupcake.

Frost the stuffed cupcake with the coconut buttercream, and sprinkle with cinnamon if you're feeling fancy.