Chill your can of coconut milk overnight. This helps the cream separate from the liquid. Place a mixing bowl and beaters in the fridge for 15–20 minutes before starting for best results.
Scoop out the solid coconut cream. Open the can without shaking it.
Spoon the thick cream into your cold bowl. Save the remaining liquid for smoothies or sauces.
Add sweetener, cocoa, vanilla, and salt. Start with the lower amount of sweetener if you prefer a darker chocolate flavor, then adjust later to taste.
Whip until light and fluffy. Using a hand mixer or whisk, beat for 2–4 minutes until the mixture is smooth and aerated. If it looks too loose, sprinkle in a small pinch of xanthan gum and beat 20–30 seconds more.
Taste and tweak. Add more sweetener for a sweeter mousse, a splash more vanilla for warmth, or a dash of espresso powder for mocha depth.
Whip briefly to combine.
Pipe or spoon into serving dishes. Small ramekins or glass jars work well. This recipe makes 3–4 servings, depending on size.
Chill to set. Cover and refrigerate for at least 1 hour for the best texture. The mousse will thicken as it chills.
Garnish and serve. Top with a little shaved dark chocolate, berries, or toasted coconut for texture and a pretty finish.