1⅔ cups oats (quick-cooking or old fashioned)
½ to ¾ cup granulated sugar (use less for a mildly sweet bar; omit altogether if your add-ins are super sweet)
⅓ cup oat flour (or ⅓ cup oats, finely ground in a food processor or blender)
2 tablespoons finely ground flax seed (optional)
½ teaspoon salt
½ teaspoon ground cinnamon
2 to 3 cups dried fruits, nuts, chocolate, coconut, seeds, etc. (total of 10 to 15 ounces)
⅓ cup peanut (or other nut) butter
1 teaspoon vanilla extract
6 tablespoons melted butter
¼ cup honey or maple syrup
2 tablespoons corn syrup
Heat oven to 350º. Line the bottom of an 8-inch square pan with foil or parchment, leaving an overhang of a couple inches on two opposite sides of the pan. Lightly grease the foil/parchment and exposed sides of the pan.
In a large bowl, stir together the oats, sugar (if using), oat flour, flax, salt, cinnamon and any dry add-ins. In a medium bowl, whisk together the peanut butter, vanilla, melted butter, honey and corn syrup until a smooth mixture forms. Immediately pour this mixture into the bowl with the oats, and use a rubber spatula to combine. Continue stirring until the oats are well coated with the liquid mixture.
Transfer the granola mixture to the prepared pan and press firmly, taking care to ensure the corners of the pan are filled. Bake for 30-40 minutes, until the top is nicely browned. Cool the pan on a wire rack for about 20 minutes, then transfer the uncut bars to the rack to cool completely. Once cool, place the uncut bars in the refrigerator for 30 minutes prior to cutting. Once cool, cut into bars/squares. Wrap the individual bars in plastic wrap and store in the refrigerator (this will prevent them from becoming too crumbly and make them easier to eat).