Chop 1 bar of Newfoundland Chocolate Company cooking chocolate into approx. 1/4-inch pieces. Set aside in a stainless-steel bowl. In a pot, bring cream and butter to a gentle boil about (78°C). Pour hot cream over chocolate and let sit for 2-3 minutes. Mix gently, as not to incorporate too much air, with a wire whisk starting in the centre and working outward until smooth. Transfer to a shallow dish and refrigerate, uncovered, for 20 minutes. Cover with wrap and refrigerate until firm yet pliable, about 2 hours or overnight. Use a spoon to scoop ganache into bite-sized pieces and roll in to balls. Toss each ball in dark cocoa powder, and stack neatly on your favourite tray or plate.