Preheat your oven to 350°F. Grease a 9x13-inch baking pan or line it with parchment paper for easy removal.

In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.

In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.

Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the red, white, and blue M&M's and white chocolate chips until evenly distributed.

Spread the cookie dough evenly into the prepared baking pan.

Bake for 20-25 minutes, or until the edges are golden brown and a toothpick inserted in the center comes out clean.

Allow the cookie bars to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely. Cut into squares and serve.