Preheat oven to 160 degrees Celsius. Grease a 9-inch square baking tin and line with baking paper, extending two of the sides (see photo below.)
Combine sugar, evaporated milk and butter in a saucepan. Cook over medium heat, stirring with a wooden spoon constantly until the butter has melted and the mixture has come to a boil. Remove from heat and stir in chocolate until all of the chocolate has melted.
Beat in eggs and vanilla essence. Gently stir in flour and baking soda until incorporated. Pour batter into prepared baking tin. Bake for 30 to 35 minutes. Leave brownies to cool in tin and using the extended sides of the baking paper, life the brownies out. Cut into 16 squares. Dust with icing sugar and top each with a scoop of vanilla ice cream and serve immediately.