Place the quinoa into a bowl and cover it fully with hot water. Let it soak for at least 1 hour to soften.
Preheat your oven to 400°F and line a 6 x 8 inch baking pan with parchment paper.
In a separate small bowl, combine the ground flaxseeds with 1½ fl oz (3 tablespoons) of water. Mix well and allow it to sit for about 10 minutes to thicken into a gel-like texture.
Once the quinoa has soaked, drain the water. Add the quinoa to a food processor along with the yogurt, banana, cacao powder, prepared flaxseed mixture, maple syrup, vanilla extract, peanut butter, and baking powder. Blend everything together until the mixture becomes smooth and uniform.
Gently fold in a portion of the chocolate chips into the batter.
Transfer the batter into the lined baking pan and smooth out the top. Sprinkle additional chocolate chips over the surface if desired.
Bake in the preheated oven for 20–25 minutes, or until a skewer inserted into the middle comes out with just a few moist crumbs (the brownies should be set but remain soft inside).
Remove from the oven and allow the brownies to cool completely in the pan before slicing and serving.