In shallow bowl, stir together Bisquick mix and Cajun seasoning. Coat shrimp with mixture. In 10-inch nonstick skillet, melt half of the butter over medium heat. Add half of the shrimp; cook 3 to 5 minutes, stirring constantly, until shrimp are pink. Repeat with remaining butter and shrimp. Spoon shrimp over tomato mixture in each baking dish.