Melt chocolate chips in a double-boiler over medium heat, stirring frequently (see TIP D for details). Once fully melted, remove the chocolate from the heat and dip the unsalted side of each granola bar into the chocolate. Fully coat the bottom half of each bar then set them to rest (dipped side down) on a baking sheet lined with parchment paper. Put the bars back in the freezer to set for an additional 30-60 minutes before wrapping.
TIP A: If you don't have quick oats, then use traditional rolled oats and give them a quick spin in the food processor. Do not substitute instant oats for quick oats—they're actually quite different. The difference between steel-cut, rolled (or old-fashioned), quick, and instant oats is in the pre-rolling, -cutting, and -steaming process. Steel-cut have not been rolled at all. They're simply cut. Rolled and quick oats are both rolled (obviously!) and partially pre-steamed. The quick variety is then cut down into smaller bits that cook faster. Instant oats are pre-steamed for even longer than rolled and quick oats and cook the fastest.
TIP B: These bars can easily be made nut-free by substituting sunflower seed butter for peanut butter and using only a variety of seeds where the recipe calls for 1-cup nuts or seeds. You may also use other nut butters (like almond or cashew) in the place of peanut butter if more to your liking.
TIP C: Chocolate is like wine—you only want to cook/bake with a type that you would consume on its own (actually, shouldn’t this be the case with all ingredients?!?). I recommend always springing for the good stuff, but this is particularly important when making a chocolate ganache or glaze. Higher quality chocolate chips (or wafers) have minimal stabilizers which means that they melt more easily. They’re also a bit more forgiving if you need to heat and re-heat them. Of course, you could also use a solid block of chocolate and break it into small bits before melting, but why go to that extra trouble? Guittard® and Ghiradelli® semisweet and bittersweet chocolate chips have never let me down.
TIP D: A "double-boiler" is an actual kitchen tool, but few home kitchens have them—likely because they take-up a lot of space and the work-around is often easier and equally successful. To mimic a double-boiler, fill a medium-size saucepan with about 1 inch of water. Bring the water to a gentle simmer and then put a glass bowl that can handle high heat on top of the saucepan so that the bottom of the bowl fits about half-way into the pan but does not touch the water. Keep the water in the saucepan at a gently simmer and add your chocolate chips to the glass bowl. Voilà—you have a double-boiler!