Heat oven to 350°F. Spray 8-inch square (2-quart) glass baking dish with cooking spray. In large bowl, stir bread mix, water, oil and eggs 50 to 75 strokes with spoon until mix is moistened.
Sprinkle cranberries in baking dish. Spoon and spread batter evenly over cranberries. Sprinkle with brown sugar. Pour boiling water evenly over batter.
Bake 35 to 40 minutes or until cake is golden brown and top springs back when touched lightly in center. Cool at least 30 minutes.
To serve, cut cake into squares; invert squares onto individual dessert plates. If desired, top with sweetened whipped cream. Store in refrigerator.