Preheat oven to 180°C. Line a small baking dish with baking paper.
Place butter and brownie mix in a medium pot on medium heat. Stir continuously, until butter has melted. Remove from heat.
In a large bowl, whisk eggs with electric beaters for about 3 minutes until pale and fluffy. If you don't have an electric beater, beat eggs with a whisk or fork.
Pour chocolate mixture and flour into eggs and mix quickly to combine.
Transfer to prepared dish and bake for 30 minutes, the top should be cracked and the brownie gooey in the middle.
Serve in bowls with cream or ice cream.