Coat 12-cup muffin-pan tin with nonstick cooking spray.
Combine brown sugar, 1/4 cup flour, and cinnamon in small bowl. Work in butter until mixture is crumbly. Stir in chocolate.
Combine 2 cups flour, granulated sugar, baking soda and salt in bowl. Remove 1/2 cup; set aside. Add cocoa powder to remaining flour mixture.
Beat cream cheese and 1 of the eggs in small bowl until smooth. Stir in reserved 1/2 cup flour mixture.
Beat remaining egg, water, oil and vanilla in bowl. Add cocoa mixture.
Using two-thirds cocoa batter, fill muffin cups half full. Using remaining cocoa batter and cream cheese batter, spoon batters side by side in each cup. Sprinkle with streusel.
Bake in 350 degree F oven 22 to 25 minutes or until done. Cool on rack 5 minutes. Serve warm.