In a small bowl, mix the flour, baking powder and salt. Set aside.
In a stand mixer with the whisk attachment, cream the butter and brown sugar on medium low speed.
Add the egg and vanilla and mix until well combined and smooth.
Add the flour mixture slowly on low to medium-low speed until well blended.
Remove the bowl from the stand mixer and mix in the chocolate chips and walnuts manually with a spatula.
On a lined baking sheet, use two spoons to scoop out the cookie dough and place on baking sheet leaving about 2” in between each cookie. Bake for 15 min and enjoy!