In a large bowl, place strawberries, blueberries, blackberries and raspberries, add orange juice, orange zest, lemon juice, lemon zest and optional Grand Marnier, sugar, cornstarch and cinnamon; mix lightly. Let set for 5 minutes. Meanwhile make streusel topping. In a medium bowl combine butter, sugar and cinnamon, mix well with a fork. Add flour and mix until crumbly.
Place berry mixture into a souffle dish. Top with streusel topping. Place in center of cooking grate. Cook 40 minutes or until brown and bubbly.
Note: may be made in individual souffle dishes, cooking time is 15 to 20 minutes. Serve with vanilla ice cream.