01 - Preheat oven to 350°F. Line a 9x13-inch baking pan with parchment paper, leaving an overhang for effortless removal.
02 - Whisk together the flour, baking soda, salt, and cinnamon in a medium mixing bowl.
03 - In a large bowl, whisk the melted butter, brown sugar, and granulated sugar until smooth. Incorporate eggs and vanilla extract until fully combined.
04 - Gradually stir the dry mixture into the wet ingredients using a spatula or wooden spoon, mixing only until combined without overworking the dough.
05 - Gently fold in chocolate chips, sprinkles, and nuts if using, reserving a portion of chips and sprinkles for garnish.
06 - Distribute dough evenly in the prepared pan. Sprinkle reserved chocolate chips and sprinkles over the surface.
07 - Transfer to the oven and bake for 23 to 27 minutes, until edges are golden and a toothpick inserted in the center yields moist crumbs.
08 - Allow bars to cool completely in the pan. Use the parchment overhang to lift out, then slice into bars.