Preheat oven to 350 degrees. Butter a 9 by 9-inch (or 11 by 7-inch) baking dish, set aside.
In a large mixing bowl whisk together 3/4 cup (150g) granulated sugar, flour, 1/4 cup (25g) cocoa powder, baking powder and 1/4 tsp salt for 20 seconds. Pour in milk, melted butter and vanilla and stir with a rubber spatula or wooden spoon until well blended. Spread batter evenly into prepared baking dish.
In a mixing bowl whisk together remaining 1/2 cup (100g) granulated sugar, brown sugar, remaining 1/4 cup (25g) cocoa powder and remaining 1/4 tsp salt. Pour mixture over batter and spread into an even layer. Carefully pour hot water evenly over top, do not stir.
Bake in preheated oven 35 - 40 minutes until center is nearly set (it should still wiggle slightly). Remove from oven and let stand for 10 - 15 minutes before serving. Serve in bowls topped with strawberries, bananas, ice cream and pecans if desired. Garnish with mint. Serve immediately.