3 extra-large whole eggs
In a large heat-proof bowl (we used a glass bowl), whisk together the 3 whole eggs, 3 egg yolks, 1 cup sugar, the lemon zest, lemon juice, and a pinch of salt. Place the bowl over a pan of simmering water and cook, whisking constantly, for about 10 to 12 minutes until the mixture is thick like pudding. Take off the heat and set aside for 15 minutes to cool. Cover with plastic wrap directly on the surface and refrigerate for 1 to 2 hours, until completely chilled.
In a small bowl or cup, mix the measured lemon curd to soften it. Remove custard from fridge and stir in the lemon curd. In a separate bowl, place half the egg whites and a pinch of salt. Whisk with an electric mixer on high speed. After about a minute, add the remaining 2 tablespoons sugar and continue to beat until the whites are stiff and shiny. Carefully fold the beaten whites into the cold lemon mixture with a rubber spatula. Place the cream in the same bowl (you can also use a Kitchen Aid mixer fitted with the whisk attachment) and beat with electric mixer on high speed until the cream forms stiff peaks. Carefully fold the whipped cream into the lemon mixture. Pour mousse into large souffle dish or evenly among individual ramekins (6-8 small ones and 4 medium ones). Dollop with fresh whipped cream and your choice of berries. Chill and serve cold.