1. Preheat oven to 180 C / Gas mark 4. Grease and flour a 20cm square baking tin.
2. In a large saucepan, melt 125g butter. Remove from heat, and stir in sugar, eggs and 1 teaspoon vanilla. Beat in 5 tablespoons cocoa, 50g flour, salt and baking powder. Spread batter into prepared tin.
3. Bake in preheated oven for 25 to 30 minutes. Do not overcook.
4. To make icing: Combine butter, cocoa, honey, vanilla and icing sugar. Ice brownies while they are still warm.