Pre-heat the oven to 180C.
Grease a 32cm x 20cm disposable foil baking tin.
Melt the chocolates, butter and sugar together over a low heat.
Once they are melted, remove from the heat and leave to cool for 5 or 10 minutes.
Beat in each egg, one by one.
Stir in the flour.
Put half of the batter in each of the tin to cover the base.
Spread half of your raspberries and half or your chopped Oreos over this batter evenly, so you get some in each bite.
Spread the rest of the batter over the top.
Put the remaining raspberries and Oreos on top of this.
Bake for about 25 minutes. A skewer should come out only just clean. You could test at 20 minutes and again at 23 minutes just in case.
As always, remember that depending on your oven and the tin size you use it could take up to 10 minutes longer, but please please try not to overcook them. Brownies are always better under-done than over.