Remove a large egg from the fridge, set on the counter for 30 minutes to become room temperature.
Place the butter in a small sauce pan on medium heat to come to a simmer. Watch the butter during the browning process to avoid burning. Stir periodically to check the color of your butter to remove from heat promptly, whisk in the milk powder at the very end. Simmer for approximately five to six minutes.
Pour the butter into a microwaveable bowl and mix with the sugar to dissolve as the butter cools. Allow the butter to cool for approximately 15 minutes on the counter.
Once your butter has cooled, grab a large mixing bowl to begin combining the wet ingredients. If the butter has solidified and is no longer mixable, microwave for 10-15 seconds.
Pour the butter and sugar mixture into the mixing bowl and add vanilla extract. Begin creaming the butter and sugar with a hand mixer for approximately two minutes.
Crack egg into bowl to add to the creamed mixture, mix wet ingredients on medium mixer speed.
Sift the flour in a separate bowl, add the cinnamon powder, salt, baking soda and cornstarch to combine the dry ingredients.
Add ½ cup of the dry mixture at a time to the batter by folding together gently until well combined, avoid over mixing.
Pour the chocolate chips into the batter and fold gently.
Scoop the cookie batter using an ice cream scooper and roll into a ball. Once the dough is in an even ball, use your palm to shape the cookie into a shape similar to a hockey puck (circular but not too flat). Avoid baking your cookies in the shape of a ball to avoid a dome shape while baking.
Allow the cookie dough to cool in the fridge for approximately 30 minutes, cover with Saran Wrap while in the fridge chilling.
Preheat the oven to 350 degrees and line your baking sheet with parchment paper. Place each cookie on the baking sheet a few inches apart to leave space for spreading, about three fingers width apart.
Bake the cookies for 9-11 minutes on the middle oven rack. Remove the cookies from the oven, the cookies should be evenly spread. Allow the cookies to cool for five minutes on a wire rack or countertop before serving.
Indulge while warm and store any leftovers in an air-tight container.