Preheat the oven to 175°C. Grease and flour an 8-inch square pan.
In a large saucepan, melt 1/2 cup butter. Remove from heat, and stir in sugar, eggs, and 1 teaspoon vanilla. Beat in 1/3 cup cocoa, 1/2 cup flour, salt, and baking powder. Spread batter into prepared pan.
Bake in a preheated oven for 25 to 30 minutes. Do not overcook.
To Make Frosting: Combine 3 tablespoons softened butter, 3 tablespoons cocoa, honey, 1 teaspoon vanilla extract, and 1 cup confectioners' sugar. Stir until smooth. Frost brownies while they are still warm.