Preheat your oven to 170°C (340°F). Line an 8x8-inch square baking pan with parchment paper, leaving overhang on the sides for easy lifting.
Add the 1 cup cottage cheese to a blender or food processor. Blend until completely smooth and creamy. This step is essential—no lumps should remain. The texture should resemble thick yogurt.
In a large mixing bowl, whisk together the 2 eggs, ¾ cup granulated sugar, and ¼ cup light brown sugar until pale and slightly thickened, about 1–2 minutes.
Slowly pour in the ½ cup melted butter while whisking continuously. Add the 1 teaspoon vanilla extract and mix until smooth.
Stir in the blended cottage cheese until fully incorporated. The mixture should look glossy and creamy.
Sift in the ¾ cup cocoa powder, ½ cup flour, ¼ teaspoon salt, and ½ teaspoon baking powder. Gently fold with a spatula until just combined. Do not overmix—stop as soon as no dry streaks remain.
Fold in the ½ cup dark chocolate chips evenly throughout the batter.
Pour the batter into the prepared pan and spread evenly with a spatula. Tap the pan gently on the counter to release air bubbles.
Bake for 25–30 minutes. The top should be set with a crackly surface, and a toothpick inserted in the center should come out with a few moist crumbs but not wet batter.
Allow the brownies to cool completely in the pan before slicing. For ultra-clean cuts, refrigerate for 30–45 minutes before cutting.
