Preheat oven to 350°F. Line a cupcake pan with cupcake liners; set aside.
In a bowl fit with a mixer, beat sugar and butter until creamed, about 3 minutes.
Add eggs, one at a time. Increase speed to medium. Mix for 3 minutes.
Mix in vanilla extract, salt, baking soda, baking powder, and cinnamon.
Slowly mix in heavy cream.
Mix in flour, a little at a time.
Mix in sour cream until incorporated.
Spoon batter into muffin tin ½ full.
Bake in oven 350°F for about 22 minutes or until the center of the cupcake comes out clean with a toothpick. Allow to cool completely.
Beat softened butter, cinnamon, and confectioners' sugar for 3-5 minutes.
Beat in ¼ softened cream cheese at a time.
Beat in vanilla extract and a pinch of salt. Beat for an additional 3 minutes. Fill a cupcake liner bag with frosting. Refrigerate frosting for about 30 minutes.
Use a cupcake tip (such as a Russian Cake Tip) to frost cupcakes. Make churros and top cupcake with a small piece of it using leftover frosting to get it to stick to the top.