Preheat oven to 350°F. Grease and line a 9 inch spring form pan with baking paper.

Combine sugar, melted butter and water in a large bowl. Stir in the eggs and vanilla.

Combine the flour, cocoa and baking powder and stir this micture into the sugar mixture along with the nuts.

Spread into the prepared tin and bake for 20-30 minutes or until a wooden skewer inserted into the center comes out slightly sticky. Cool completely in the tin.

To make the marshmellow topping. Pour the cream into a saucepan along with the marshmellows and stir constantly over a very low heat until the marshmellows have melted.

Pour this mixture over the cooled brownie base and spread to the edges of the pan. Refrigerate until the topping has set.

To serve. Remove from pan and place on serving platter.Decorate with whipped cream, grated chocolate & strawberries/ cherries or whatever you prefer! Slice into wedges and indulge!