1. Preheat oven to 350 degrees. Spray two 12-cup muffin pans with vegetable cooking spray.
2. In the top of a double boiler, whisk together 1 egg yolk and 1 cup of the milk. Stir in brown sugar and cocoa and add chopped chocolate. Over medium-high heat, bring water in the bottom of the boiler to a low simmer and cook the mixture, stirring constantly, until sugar is dissolved and chocolate is melted, about 5 minutes. (Reduce heat to medium if water begins to boil.) Mixture should thicken slightly. The melted chocolate may be in tiny bits, but that's OK. Remove from heat and let cool slightly.
3. In a large bowl, use an electric mixer on medium speed to cream butter and 1/2 cup of the sugar until light and fluffy, about 2 minutes. Beat in remaining 2 egg yolks and vanilla.
4. Add half the chocolate mixture and beat until smooth. Add 1 cup of the flour, baking soda, and salt. Mix just until incorporated, then add remaining chocolate and remaining 1/4 cup milk and mix until smooth. Add remaining 3/4 cup flour and mix until well incorporated.
5. In a separate bowl, use an electric mixer or a whisk to whip egg whites until soft peaks appear. Gradually add remaining 1/4 cup sugar and beat until stiff peaks form. Fold a third of the egg whites into the chocolate mixture until smooth, then gently fold in remaining whites until smooth.
6. Divide batter evenly among prepared pans. Bake until a toothpick inserted in the center of a cupcake comes out clean, about 11 to 12 minutes. Let cupcakes rest in pan 1 minute, then transfer to a wire rack to cool, about 30 minutes.
7. When cupcakes are cool, prepare the frosting. In the top of a double boiler, stir together egg white, water, sugar, cream of tartar, and salt. Bring the water in the bottom pan to a simmer over medium-high heat(lower to medium if necessary to maintain the simmer). Use an egg beater or electric mixer on high to beat mixture constantly. Continue beating until thick and fluffy and slightly stiff, 7 to 10 minutes. Remove from heat, addvanilla, and beat to mix.
8. Place cooling rack over a sheet of waxed paper. Spread frosting on cupcakes. If desired, sift cocoa over the tops. Let rest 30 minutes sofrosting can thicken slightly; then serve. Store in a single layer in a covered container at room temperature for 1 day, or freeze.
Source: Hannaford fresh Magazine, September - October 2012