1. Curd: Cut butter into 8-12 pieces, put in freezer while heating the curd ingredients.
2. Blend remaining ingredients together with an immersion blender in top of a double boiler.
3. Heat slowly with stirring to 170°F or until thick enough to coat spoon.
4. Remove from heat and add butter with stirring until butter is melted.
5. Refrigerate until cool with plastic wrap on surface to prevent skin forming (1-2 hr).
6. Mousse: Whip cream with vanilla and sweetener.
7. Fold chilled curd into whipped cream and top with berries or mint if using.

*liquid sweetener preferred such as Torani or Davinci.