Melt the chocolate. Place the chopped dark chocolate in a microwave-safe bowl and heat in 20–30 second bursts, stirring between each, until smooth. Or melt gently over a double boiler. Let it cool for 2–3 minutes so it’s warm but not hot.

Blend the base. Add cottage cheese, sweetener, and vanilla to a high-speed blender or food processor. Blend on high for 30–60 seconds until completely smooth and glossy. Scrape down the sides as needed. You shouldn’t see any curds.

Add the chocolate. With the blender running on low, stream in the melted chocolate. Blend until fully incorporated and the mixture looks thick and uniform. Taste and adjust sweetness if needed.

Chill to set. Spoon the mousse into small jars or bowls. Refrigerate for at least 30–45 minutes. It will thicken further as it chills.

Serve. Top with berries, a sprinkle of flaky salt, or shaved chocolate. Serve cold.