Preheat your oven to 180°C (350°F). Line an 8 x 8-inch baking pan with parchment paper, ensuring the paper extends slightly over the edges for easy removal later. Set the prepared pan aside.

In a microwave-safe bowl, add your chopped chocolate. Melt the chocolate in the microwave in short bursts, stirring occasionally until smooth. Let it sit for 1-2 minutes to cool slightly. Then add yogurt and sugar to the melted chocolate. Whisk the mixture until it is smooth and well combined. Transfer this chocolate mixture to a large mixing bowl.

Add the flour, cocoa powder, and baking soda to the chocolate mixture. Stir until just combined—be careful not to overmix. Pour in the milk and mix well until the batter is fully incorporated. If using, fold through chocolate chips gently into the batter, distributing them evenly throughout.

Transfer the prepared batter to your lined baking pan. Smooth the top with a spatula if needed. Bake the brownies in the preheated oven for 25-30 minutes, or until a skewer or toothpick inserted into the center comes out just clean, indicating they are fully baked.

Once baked, remove the pan from the oven and allow the brownies to cool in the pan for about 10 minutes. Carefully lift the brownies out of the pan using the parchment paper overhang and transfer them to a wire rack to cool completely before cutting into squares. Enjoy your delicious homemade brownies!