Preheat the oven to 350℉. Line baking sheets with silicone baking mats or parchment paper.
In a bowl, combine the flour, baking soda, salt, and cinnamon. Set aside.
2¼ cups flour, 1 teaspoon baking soda, 1 teaspoon salt, 1 teaspoon cinnamon
In a separate bowl, add the softened butter, brown sugar, sugar, eggs, and vanilla extract. Beat with a mixer until creamy.
1 cup unsalted butter, softened, 1 cup packed brown sugar, ½ cup sugar, 2 large eggs, 1½ teaspoons pure vanilla extract
Add the flour mixture and mix, starting on low, then increasing the speed, until blended. Stir in the milk chocolate and semi-sweet chocolate chips.
1 cup milk chocolate chips, 1 cup semi-sweet chocolate chips
Using a cookie scoop, drop dough onto prepared baking sheets. Bake until golden, about 10 minutes. Remove from the cookie sheet to a cooling rack to cool completely.