Preheat your oven to 350°F (175°C).

Grease or line an 8x8-inch baking pan with parchment paper.

In a mixing bowl, combine Greek yogurt, applesauce, granulated sugar, and brown sugar until smooth and creamy.

Incorporate the eggs and vanilla extract into your wet mixture, whisking until well combined.

In a separate bowl, whisk together whole wheat flour, cocoa powder, baking powder, and salt.

Gradually mix the dry ingredients into the wet mixture until just combined.

Fold in dark chocolate chips if desired.

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

Bake in the preheated oven for 20-25 minutes. Check for doneness at 20 minutes.

Allow the brownies to cool in the pan for about 10 minutes before transferring them to a wire rack.