Beat the heavy cream with an electric mixer until it is whipped, and set aside.
Melt the chocolate and butter over a double boiler on medium heat. Remove from heat and set aside.
Combine the egg yolks, 1 tablespoon water, and half the sugar in a second metal bowl and whisk over the double boiler set over medium heat. (Do not allow any additional water to splash into this bowl.) Continue to whisk and insert a candy thermometer into the mix. When it reaches 145 degrees F, remove from the heat and whip with an electric mixer until it cools. Set aside briefly.
Wash and dry the beaters for the electric mixer and wipe off the candy thermometer to have them clean for the next step. In the third metal bowl, combine the egg whites with the remaining 1/8 cup sugar and whisk over the double boiler until the candy thermometer reaches 145 degrees F. Then, remove from the heat and beat with the electric mixer until the whites are stiff.
Fold the egg whites into the egg yolks. Fold the chocolate into the eggs, then fold in the whipped cream. Spoon into martini glasses or serving cups. Refrigerate for at least 4 hours or overnight.
For the toppings and garnish:
Use an electric mixer to beat the heavy cream until whipped. Slice each strawberry up to the stem and spread into a fan. Garnish chilled mousse with whipped cream and strawberries just before serving.
For this recipe it is easiest to have a series of stainless steel bowls available which you can use in succession over a pot, double boiler method. (The bowls should be of a size which will nest inside the pot with interior clearance of an inch or so for the boiling water.)