You've heard of a pizza pie - it is only logical that the next step would be pizza cake. Canadian pizza chain Boston Pizza has created this six-tier, cheese-laden, 5,000 calorie behemoth as part of its series 'pizza game changers'. Customers are invited to vote on which outlandish pizza mutation or accessory they would like to see the company make - other inventions include a gas-powered pizza cutter, a lockable pizza protector and a handy pair of pizza cheese clippers. Standing at just under six inches high, Pizza cake has been a runaway success, receiving over 15,000 votes - beating...