Preheat oven to 350º...Grease and flour 2 9 inch pans...In saucepan melt chocolate squares & butter on LOW heat...Combine flour, sugar, cocoa powder, baking powder & salt...w/ electric mixer... then add 1/4 cup dark & milk chocolate chips, buttermilk & eggs...beat on LOW speed for 1 minute..increase speed to high & beat for aound 2 minutes or till light & fluffy.. split batter between pans & bake for about 25-30 minutes or until cake springs back if gently pressed...Cool in the pans at least 5 minutes then invert onto a wire rack & let completely cool. In saucepan bring to a boil then remove from heat immediately the whipping cream & add the remaining 1 1/2 cups of semisweet chocolate chips..stir until frosting is smooth & starts to thicken....frost the cooled cake & enjoy!