Chill your tools. For fastest results, place your mixing bowl and beaters in the fridge or freezer for 5–10 minutes. Cold equipment helps the cream whip quickly and hold its shape.

Measure dry ingredients. In the bowl, whisk together the cocoa powder, powdered sweetener, and a pinch of salt to break up any lumps. This prevents dusty pockets of cocoa in the mousse.

Add liquids. Pour in the cold heavy cream and add the vanilla extract. If you’re using espresso powder or another extract, add it now.

Whip to soft peaks. Using a hand mixer (or whisk and strong arms), beat on medium speed until the mixture thickens and the beaters leave soft trails. This usually takes 1–2 minutes.

Stop at firm peaks. Continue whipping on medium-high until you get firm, glossy peaks that hold when you lift the beaters. Don’t go past this point or the mousse can turn grainy.

Taste and adjust. Give it a quick taste. If you want more sweetness or deeper chocolate, sprinkle in a little more sweetener or cocoa and beat briefly to combine.

Serve or chill. Spoon into small bowls or glasses. It’s delicious right away, but 30–60 minutes in the fridge firms it to a classic mousse texture.

Finish with toppings. Add berries, a few shaved curls of sugar-free chocolate, or a sprinkle of chopped nuts for crunch.