In a heatproof bowl, combine the chocolate and butter. Preheat the oven to 350F degrees. Let cool until spreadable. Using a handheld whisk, stir the mixture until the chocolate and butter melt and are smooth. Grease (with butter) and flour 3 round 8'' cake pans, then line with parchment paper. In a small saucepan over medium-high heat, bring the cream just to a boil. Remove from the heat and immediately pour the cream over the chocolate and butter. In a large mixing bowl, mix together the butter, brown sugar, and white sugar with an electric mixer until fluffy.