Preheat the oven to 350 degrees. Place liners in a cupcake pan, set aside.
Combine ½ cup butter and 1 cup sugar on medium speed for 2 - 3 minutes. Cream until smooth.
Add in 2 eggs, 2 teaspoon vanilla and ¾ cup milk and mix on medium low until combined.
Add in 1 ½ cup flour, 1 ½ teaspoon baking powder, 1 teaspoon salt, and 1 ½ teaspoon cinnamon and combine on low. Stop the machine, scrape down the sides and mix again until thoroughly combined.
Scoop batter into cupcake liners filling each ½ - ⅔ of the way full.
In a small bowl, combine ½ cup sugar and 2 tablespoon cinnamon for the topping.
Sprinkle about ½ of a teaspoon of the cinnamon sugar mixture over the unbaked cupcake batter and use a butter knife to swirl into the batter. Retain the remaining cinnamon sugar mix for later.
Bake in the preheated oven for 14-16 minutes or until just slightly golden brown and the center is set.
For the frosting - in the bowl of the stand mixer, combine 2 cups of the powdered sugar, 1 cup butter, 1 teaspoon vanilla, 1 teaspoon salt and 1 tablespoon cinnamon.
Mix on low speed until combined.
Add in the remaining powdered sugar and the milk and mix on low until combined. Scrape the sides often.
Once combined, bump up the speed to medium and mix for an additional minute or until the frosting is smooth and fluffy looking.
Transfer the frosting to a piping bag fitted with a large star tip.
Pipe a large mount of frosting on top of each cupcake and sprinkle with remaining cinnamon and sugar mixture.