A version without butter, somehow.
The risk of salmonella from raw eggs has been somewhat overstated–there’s a risk, it’s just far lower than thought. (Salmonella tends to live on the outside of the egg when it’s the eggs that are the culprit at all.) While you can use pasteurized eggs, the mousse won’t be quite as light, because the pasteurization process impairs the ability of the white to hold air. That doesn’t mean you can’t use them, it just means the mousse will be a bit less airy.
These really are the two options, really. You can add liquor, but it won’t be enough to disinfect anything that might be going wrong; and even if you mix the chocolate mixture in while still hot, it wouldn’t be hot enough to hold the necessary temperature for long enough.
From a box sold in Chicago, Illinois.
Mousse au Chocolat
1 pkg. Baker’s semi-sweet chocolate chips
1/4 cup light or heavy cream
4 egg whites
4 egg yolks, slightly beaten
Dash salt
1 tsp. vanilla
2 Tbsp. sugar
Heat chocolate over hot water until partly melted, then remove from hot water and stir rapidly until entirely melted. Add cream and blend. Add salt and vanilla.
Add chocolate mixture to slightly beaten egg yolks and continue heating until mixture is thick and creamy (about 2-3 minutes).
Beat egg whites until foamy throughout. Add sugar gradually, beating until mixture will stand in stiff peaks. Fold chocolate mixture into egg whites only until blended. Pour into demitasse cups or small custard cups.
Chill 3-4 hours or overnight. Makes 8-10 servings.