Line a 9x9 inch baking pan with parchment paper, leaving some overhang on the sides. This will make it easier to lift the bars out once they are set.

In a large mixing bowl, combine the rolled oats, peanut butter, honey, cocoa powder, and salt. Use a spatula to mix until all ingredients are well incorporated. The mixture should be thick and sticky.

Fold in the chocolate chips until evenly distributed throughout the mixture.

Transfer the mixture into the prepared baking pan. Using the back of a spatula or your hands, press the mixture firmly and evenly into the pan. This step is crucial as it helps the bars hold together once set.

If using, sprinkle the chopped nuts and coconut flakes evenly over the pressed mixture, gently pressing them in to adhere.

Place the pan in the refrigerator for at least 1 hour to allow the bars to set. This will help them firm up and makes cutting easier.

Once set, lift the bars out of the pan using the parchment paper overhang. Cut into 12 equal squares or rectangles, depending on your preferred size.

Store any leftovers in an airtight container in the refrigerator for up to a week.