Preheat oven to 350º. Line the bottom and sides of a 9x9 or 11x7 inch metal baking dish with parchment paper or spray with cooking spray. Combine all the ingredients in a medium bowl, mix until moist and evenly distributed.

Using a large spoon or spatula, spread the mixture in an even, thin layer in the baking dish. Press down firmly to pack the mixture in. Bake until light brown on edges, about 35 to 40 minutes. Cook less time for chewy bars and more time for crunchy bars. Cut into 12 bars two parallel cuts in one direction, three parallel cuts in the other direction while they are still hot, allow to cool slightly and remove from dish to continue cooling. Store in individual resealable snack bags for up to three days or freeze them.