Chill your tools: Place a mixing bowl and whisk or beaters in the fridge for 10 minutes.
Cold tools help the cream whip faster and hold better.
Whisk the dry ingredients: In a small bowl, sift or whisk together the cocoa powder, powdered sweetener, and a pinch of salt. Sifting prevents lumps and keeps the mousse smooth.
Start the cream: Pour the cold heavy whipping cream into your chilled bowl. Add vanilla extract.
Begin whipping on medium speed until the cream is slightly thickened and soft peaks are just starting to form.
Add the chocolate mixture: With the mixer on low, gradually sprinkle in the cocoa-sweetener blend. Once it’s incorporated, increase to medium-high and whip just until medium-stiff peaks form. The texture should look glossy and hold gentle peaks.
Taste and adjust: If you want it sweeter or more chocolatey, lightly dust in a bit more sweetener or cocoa and briefly whip again.
Don’t overmix.
Optional boost: For deeper flavor, fold in 1–2 teaspoons of espresso powder or 1–2 ounces of melted, cooled sugar-free chocolate. Fold gently with a spatula to keep the mousse airy.
Portion and chill: Spoon the mousse into small ramekins or glasses. Chill for 30–60 minutes for the best texture.
It will thicken slightly as it rests.
Finish and serve: Top with a dollop of whipped cream, a few chocolate shavings, or a handful of berries. Serve cold.