Preheat your oven to 350°F.
Grease an 8x8-inch baking pan or line it with parchment paper.
In a medium bowl, whisk together the flour, cocoa powder, baking powder, and salt.
In a large bowl, mix the granulated sugar, brown sugar, Greek yogurt, vegetable oil, eggs, and vanilla extract until smooth.
Gradually add the dry ingredients to the wet mixture and stir gently until just combined. Fold in chocolate chips if using.
Pour the batter into the prepared baking dish and spread evenly.
Bake for 20-25 minutes, checking for doneness with a toothpick.
Allow the brownies to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.
Cut into squares and enjoy!