I once saw Nigella Lawson made a quicker Seven Minute Frosting using something called Instant Meringue Powder which is hard to find here in the states (and a bit pricey) so I searched the internet and found this recipe HERE.
I played around with the recipe a bit for my chocolate cake and used very strong espresso in place of the water and it was a perfect compliment for my chocolate cake, giving it a subtle mocha flavor.
Notes: This frosting is best the first day it is made, after which it will start to deflate a bit, although still tasty.
Also, It is best not to make this frosting on a rainy day or when it is very humid. The moist air will keep the frosting from fluffing up!
2 large egg whites
1 cup sugar
1/4 teaspoon cream of tartar
1/3 cup water (Or very strong espresso for a slightly coffee flavored frosting)
1/8 teaspoon salt
1 teaspoon vanilla extract (You can also play around with the extract to suit your cake such as almond, rum, or peppermint extract)
Place the 2 egg whites in a large mixing bowl or the bowl of your stand mixer.
Beat until the egg whites are foamy and thick; they should mound in the bowl, without holding a peak. Set them aside while you prepare the sugar syrup.
Combine the sugar, cream of tartar, water, and salt in a saucepan. Bring to a boil, stirring frequently; the sugar should be dissolved. If the sugar hasn’t dissolved, cook and stir a bit more, until it has. (Just cook until dissolved but no longer or else it will caramelize, I tested it by removing from heat and looking for any sugar in the bottom)
Begin to beat the egg whites, and immediately pour the boiling sugar syrup into the egg whites in a slow stream, beating all the while. As you beat, the mixture will thicken.
Once all the syrup is added, stir in the vanilla, and continue to beat till the frosting is thick and will hold a peak.
Spoon the hot frosting atop the cooled cupcakes, (or sheet or layer cake) swirling it decoratively.
Decorate while warm with sprinkles, mini chocolate chips, sparkling sugar, or the decorations of your choice, if desired.