Melt the chocolate in the top of a double boiler or in a stainless steel bowl set over simmering water. Be sure that the water does not touch the bottom of the bowl. When the chocolate is melted, remove from the heat.
Stir together the flour, cocoa powder, and baking powder. Set aside. Using a standard mixer with the paddle attachment, beat the butter on medium-high speed until creamy.
Slowly add the sugar and mix until the mixture is completely smooth and soft. Add the eggs, one at a time, mixing well after each addition. Scrape the sides of the bowl as needed.