Chill your tools: Place a mixing bowl and beaters (or whisk) in the fridge for 10–15 minutes. Cold equipment helps the cream whip faster.
Whisk dry ingredients: In a small bowl, combine the cocoa powder and powdered sweetener.
This prevents clumps and makes the mousse smoother.
Start whipping: Pour the cold heavy cream into the chilled bowl. Beat on medium speed until it starts to thicken and soft peaks form.
Add flavors gradually: Sprinkle in the cocoa-sweetener mixture a little at a time while beating. Add vanilla and a tiny pinch of salt if using.
Whip to medium-stiff peaks: Continue beating until the mousse holds ridges and the whisk leaves defined trails.
Stop before it looks grainy or starts to separate.
Taste and adjust: If you want it sweeter or more chocolatey, add a bit more powdered sweetener or cocoa. Beat briefly to combine.
Serve or chill: Spoon into small cups or jars. Enjoy right away for a light, airy texture, or chill 30–60 minutes for a denser, silkier mousse.
Garnish: Top with a dusting of cocoa, sugar-free chocolate shavings, or a few raspberries if you like.