Prep the pan: Heat the oven to 350°F (175°C). Line an 8x8-inch pan with parchment, leaving overhang for easy lifting. Lightly spray.

Blend the cottage cheese: In a blender or food processor, blend cottage cheese until completely smooth and creamy. Set aside.

Melt chocolate and butter: In a heatproof bowl, microwave butter and chopped chocolate in 20–30 second bursts, stirring until smooth. Let cool 3–4 minutes.

Whisk in sugars: Add granulated and brown sugar to the warm chocolate mixture and whisk until glossy.

Add eggs and vanilla: Whisk in 2 eggs and 1 yolk, one at a time, then add vanilla. Mix until thick and shiny, about 30 seconds.

Stir in cottage cheese: Whisk in the blended cottage cheese until fully combined. The batter should look smooth and velvety.

Combine dry ingredients: In a separate bowl, whisk flour, cocoa, espresso powder, and salt.

Fold together: Using a spatula, fold dry ingredients into the wet mixture just until no dry streaks remain. If using, fold in chocolate chips.

Bake: Spread batter into the prepared pan and smooth the top. Bake 24–28 minutes, until the edges are set and a toothpick comes out with moist, fudgy crumbs (not wet batter).

Cool and set: Cool in the pan on a rack for at least 1 hour. For clean slices and maximum fudginess, chill 30 minutes before cutting.