Preheat the oven to 350 degrees.
In a bowl, whisk together the 1 ½ cup all-purpose flour, 1 tsp baking soda, ½ tsp baking powder, 1 tsp salt, and 2 tsp cinnamon. Set aside.
1 ½ cup all-purpose flour, 1 tsp baking soda, ½ tsp baking powder, 1 tsp salt, 2 tsp cinnamon
In the bowl of an electric mixer, add the ½ cup salted butter and ¾ cup peanut butter. Cream together on medium speed for about a minute. Add the ¾ cup brown sugar and ¼ cup granulated sugar and beat for an additional 2 minutes.
½ cup salted butter, ¼ cup granulated sugar, ¾ cup peanut butter, ¾ cup brown sugar
Add the 1 tbsp whole milk, 1 large egg, and 2 tsp vanilla extract and beat to combine. Add the dry ingredients and mix on medium speed until combined into a dough.
1 tbsp whole milk, 1 large egg, 2 tsp vanilla extract
Line a baking sheet with parchment paper. Take 2-3 tbsp chunks of dough and roll into balls. Place them on the sheet at least 2 inches apart and use the bottom on a glass to push them down until they are about 1 inch thick.
Bake for 10-12 minutes until the edges are golden brown but the middles are still slightly soft. Let cool for 15 minutes on the baking sheet, then transfer to a cooling rack and cool for an additional 15 minutes.