Preheat your oven to 180°C (350°F) and line an 8 x 8-inch baking pan with parchment paper.

Chop your baking chocolate and melt it in a microwave-safe bowl in short bursts of 30 seconds.

Once melted, allow the chocolate to cool slightly, then whisk in Greek yogurt and sugar alternative until smooth.

In a separate bowl, combine all-purpose flour, cocoa powder, and baking soda. Whisk them together.

Pour the cooled chocolate mixture into the bowl of dry ingredients and gently fold together until just combined.

Add the milk to the batter and stir until fully incorporated. If using, fold in chocolate chips.

Transfer the brownie batter into the prepared baking pan and smooth the top with a spatula.

Bake in the preheated oven for 25-30 minutes, until a toothpick comes out with just a few moist crumbs.

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