Preheat your oven to 350°F and line an 8x8 or 9x9 inch baking pan with parchment paper, allowing the paper to overhang the sides slightly for easy removal later. Sift the cocoa powder into a small bowl to remove any lumps, which ensures a smooth, lump-free batter. Measure out all remaining ingredients and have them ready before you begin—this organized setup is critical when working with chocolate, as it sets quickly.

Melt the chocolate in a microwave-safe bowl in 30-second intervals, stirring between each interval, until completely smooth. This gentle approach prevents overheating and ensures a silky texture. Once melted, let the chocolate cool to room temperature for about 2 minutes—this step is crucial because adding cold or warm ingredients to hot chocolate can cause it to seize or create texture problems.

Once the melted chocolate has cooled slightly, stir in the greek yogurt, vanilla extract, and sugar using a spatula or whisk until fully incorporated and smooth. I find that FAGE Total 5% yogurt works best here because its higher fat content creates a richer, more indulgent crumb—don't skip this detail if you can find it. The yogurt adds moisture and a subtle tang that balances the chocolate beautifully while keeping these brownies tender.

Add the flour, sifted cocoa powder from Step 1, baking soda, and salt to the chocolate-yogurt mixture. Stir gently and thoroughly until just combined—the batter should be smooth with no streaks of flour visible. Don't overmix, as this can develop gluten and result in tough, dense brownies rather than the fudgy texture we're aiming for.

Stir the milk into the batter until fully incorporated, then fold in the chocolate chips if using. The milk creates a fudgier texture by adding moisture without excess fat, and I always include the chocolate chips because they add pockets of richness that make every bite feel indulgent. The batter should now be thick and pourable.

Pour the batter into your prepared pan and smooth the top gently. Bake for 25–30 minutes, until a toothpick inserted into the center comes out with just a few moist crumbs (not fully clean). These brownies will continue to set slightly as they cool, so avoid overbaking—they should still feel slightly underdone when removed from the oven.

Allow the brownies to cool in the pan for 10 minutes to set slightly, then transfer the entire parchment paper with the brownies to a wire cooling rack. Let cool completely before cutting into squares. Cooling completely ensures clean cuts and allows the texture to fully develop.