Add cottage cheese or Greek yogurt, protein powder, cocoa powder, sweetener, vanilla, and salt to a high-speed blender.
Pour in 1/4 cup milk and blend on high until completely smooth, 30–60 seconds. If the mixture is too thick to blend, add milk 1 tablespoon at a time.
If using, add xanthan gum or pudding mix and blend again for 10–15 seconds until the texture thickens slightly.
Taste and adjust sweetness or cocoa. It should taste slightly sweeter than you want—flavors mellow after freezing.
Fold in brownie pieces and any add-ins like mini chips. Don’t overmix; you want chunks.
Transfer to a shallow, freezer-safe container.
Smooth the top, cover, and freeze for 2–3 hours, stirring once after 60–90 minutes for even texture.
When ready to serve, let the container sit at room temperature for 5–10 minutes, then scoop and enjoy.