Preheat oven to 375 degrees fahrenheit. Line 2 baking sheets with parchment paper.
In a medium bowl, mix together flour, baking soda, cinnamon and salt. This is your dry mixture.
In a stand mixer, beat softened butter, sugar, and brown sugar until completely mixed. Scrape the sides.
Add the eggs and vanilla and mix again.
Add the dry mixture to the stand mixture. Mix until the dry mixture is completely blended with the butter mixture.
Using a small ice cream scoop, scoop the mixture and roll into a ball. Drop onto the parchment-lined baking sheets.
Bake for 10-12 minutes. Remove from cookie sheet and put on cooling rack.
Brown butter frosting
In a medium bowl, put powdered sugar, vanilla, and 3 tbsp of milk. Stir together.
In a small saucepan, heat the butter over medium heat until just light brown. Be careful not to burn.
Slowly pour browned butter over powdered sugar mixture. Beat with a hand-held mixer until smooth. If needed add 1 more tbsp of milk until frosting is spreadable. Frost the cooled cookies with the frosting.