Preheat oven to 180°C. Line a 20cm square cake or slice tin with baking paper.
Melt butter and 200g chocolate together; cool for 10 minutes before mixing in sugar, McCormick spices, eggs and flour. Spread mixture into prepared tin and bake for 30 minutes. Cool before processing half cake with rum in a large food processor until mixture comes together.
Roll heaped teaspoons of brownie mixture into balls and freeze for 5-10minutes or until they are cold. Roll the balls in 1 cup finely chopped pistachios and 1 cup finely chopped dried cranberries.