Preheat oven to 350°F. Line a cupcake pan with either paper or aluminum liners.
Mix together flour, baking powder, salt, and cinnamon in a mixing bowl.
Cream together with your mixer butter and sugar. Then add the eggs, one at a time. Mix the eggs with the butter and sugar mixture until fully incorporated.
Add dry ingredients to wet ingredients and mix thoroughly.
Stir in milk and vanilla extract.
With your electric mixer on medium speed, beat for about three minutes.
With a large ice cream scoop, fill your cupcake liners with the batter 1/2 way full.
Bake for 15 to 18 minutes.
Let cool thoroughly before adding your prepared frosting.
Frosting
Beat butter for 2 minutes on medium speed.
Add in powdered sugar and heavy cream until thick and well incorporated.
Add cinnamon and brown sugar and mix together until stiff peaks form.
Pipe frosting in an icing bag with a tip onto cooled cupcakes.