In a large bowl or the bowl of a stand mixer, beat together the butter and sugar until light and fluffy. Add the eggs one at a time, followed by the vanilla, and mix well.
Add the flour, baking powder, cinnamon, and salt and mix until a firm dough forms. Add an extra Tablespoon or two of flour if the dough is too sticky, being careful not to over mix. Chill 30 minutes.
Preheat the oven to 375ºF. Roll the dough into one inch balls and place on baking sheets lined with parchment paper. You can roll balls in cinnamon sugar for more cinnamon flavor if desired. Flatten each ball slightly with your hand or with a drinking glass to be about 1/3- to 1/2-inch thick.
Bake 7 to 8 minutes, or until the bottom is barely golden. Be careful to not over bake. Remove to a cooling rack and let cool before frosting.
Frosting
In a large bowl, beat together the cream cheese and butter with an electric mixer until light and fluffy. Beat in the powdered sugar until smooth. Add the vanilla and milk as needed to reach desired consistency. Beat until light and fluffy.
Pipe onto cooled cookies (you can use a 1M tip or snip off the top of a zip-top bag) in a spiral shape. Sprinkle the tops with cinnamon or cinnamon sugar. Store in a covered container up to 3 days.
Notes
Cinnamon sugar: For extra cinnamon flavor, roll the dough balls in cinnamon sugar before baking. You could also add in freshly grated cinnamon or mix in cinnamon chips for extra cinnamon flavor.Storage: Store in a covered container in the refrigerator 3-5 days.Freezer instructions: Allow cookies to cool completely. Place on a baking sheet and then freeze 30 minutes. Once the frosting has hardened you can stack in a covered container. Take out 1 hour before ready to serve. Variation: You could also serve these cookies with a cinnamon buttercream or drizzle with a cream cheese glaze. Note: On 2/9/24 I reduced the flour from 3 cups to 2 3/4 cups of flour after retesting them. The key to soft cookies is not over mixing and not over baking.