Preheat your oven to 350°F (175°C) and grease an 8x8-inch baking pan or line it with parchment paper.

In a medium bowl, sift together the cocoa powder, whole wheat flour, baking powder, and salt.

In a large mixing bowl, combine the granulated sugar, brown sugar, Greek yogurt, melted coconut oil (or butter), eggs, and vanilla extract. Whisk until smooth.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix.

Fold in the chocolate chips if using.

Pour the brownie batter into the prepared baking pan and spread it evenly.

Bake in the preheated oven for 20-25 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.

Allow the brownies to cool in the pan for at least 10 minutes before slicing into squares. Serve and enjoy!