Preheat oven to 350 degrees. Line an 8-inch pan with parchment paper or line with foil and grease the foil very well. In a large bowl, stir together the butter and sugar until smooth.
Add the egg and vanilla and stir to combine. Stir in the flour, salt, and cinnamon just until combined. Stir in the chocolate chips and walnuts.
Scoop the batter into the prepared pan and spread to the sides. Bake 25-28 minutes until an inserted toothpick has moist crumbs. The blondies should be slightly browned along the edges.
Cool in the pan for at least 20 minutes and then lift the brownies out by the foil/paper and set on a wire rack to finish cooling before slicing and storing in an airtight container. Enjoy!