Preheat the oven to 350F degrees and adjust the oven rack to the middle position. Line a 6-inch cake pan with a strip of parchment paper - long enough to hang over the sides of the pans. Lightly grease the pan.
Optional - Sprinkle the macadamia nuts evenly onto a small baking sheet. Toast the nuts in the oven while it is preheating for 5 - 7 minutes, or until lightly golden. Roughly chopped the nuts once cool enough to handle.
In a small mixing bowl, whisk together the oat flour, almond flour, arrowroot starch/flour, baking powder, and salt. Note - To make oat flour, add the gluten free oats to a blender or food processor and blend until ground to a fine powder/flour.
In a medium mixing bowl, add the brown sugar, granulated sugar, and melted butter. Stir until creamy and smooth. Add the egg yolk and vanilla extract and continue to stir until the egg yolk is fully incorporated.
Sprinkle the dry ingredients over the wet ingredients. Stir until no dry streaks remain. Add the chopped cherries, chopped nuts, and chocolate chips - mix until just incorporated. The dough will be thick like a cookie dough.
Pour the dough into the prepared cake pan. Press evenly into the bottom and sides of the pan with your fingertips.
Bake for 25 - 28 minutes, or until the tops are golden brown and the sides of the blondies start to pull away from the sides of the pan. Cool the blondies completely in the pan set on a wire cooling rack. To cut and serve the blondies, lift them out of the pan using the parchment overhang. The number of blondies will depend on how big you cut the blondies. Enjoy!