Blend the cottage cheese in a food processor or blender until completely smooth and creamy. Scrape down the sides to remove any lumps.
If using, add the cocoa powder and coconut oil to the blended cottage cheese and blend again until smooth.
Melt the dark chocolate in a double boiler or microwave in 30-second intervals, stirring between each, until fully melted. Let cool 2–3 minutes.
Transfer cottage cheese mixture to a large bowl. Pour in the melted chocolate and stir until completely smooth and combined.
Line an 8-inch square pan with parchment paper. Pour in the fudge and smooth the top.
Refrigerate for at least 3 hours until set. For firmer texture, freeze for an additional 30–60 minutes. Slice into 25 squares and serve cold.