Prep the strawberries: Rinse, hull, and pat them dry. Slice or roughly chop. If using frozen, thaw fully and press out excess liquid so the mousse doesn’t get watery.

Make the chocolate base: In a mixing bowl, combine mascarpone (or softened cream cheese), cocoa powder, sweetener, vanilla, and a pinch of salt. Beat with a hand mixer on low until smooth, then increase to medium. Scrape the bowl as needed to remove any cocoa clumps.

Whip the cream: In a separate chilled bowl, beat the heavy cream to medium-stiff peaks. You want it thick and billowy, not grainy. Don’t overbeat.

Fold it together: Add a third of the whipped cream to the chocolate base and gently fold to lighten it. Add the remaining whipped cream in two additions, folding slowly to keep the mousse airy.

Add the strawberries: Fold in most of the strawberries, reserving a few for topping. If you want a pinker mousse, mash a few slices before folding.

Taste and adjust: Try a spoonful and add a little more sweetener if needed. If you add sweetener, fold lightly to keep the texture intact.

Chill: Spoon into ramekins or glasses, cover, and chill for at least 30–60 minutes. Chilling firms the mousse and allows flavors to meld.

Serve: Top with the reserved strawberries and, if you like, a few shavings of dark chocolate. Serve cold.