Line an 8-inch pan with parchment paper. Set aside. If you wish to bake the bars, preheat oven to 350 F.
Stir together all dry ingredients in a large bowl. Whisk liquid ingredients together in a separate bowl, then stir wet into dry. Transfer to the prepared pan. Smooth down firmly, using a second sheet of parchment or wax paper. Press down as hard as you can.
For no-bake healthy granola bars, chill until firm. (The no-bake option is also firmer if you use coconut oil.) For baked granola bars, cook on the center rack 18 minutes, then press down firmly again. Let cool completely before cutting into bars.