Preheat oven to 180 degrees C. Coat a large baking dish with cooking spray.
Fill a large pot with lightly salted water and bring to a rolling boil. Cook pasta in boiling water until cooked through but still firm to the bite, about 12 minutes. Drain.
Place a large frypan over medium heat; cook the sausage, onion and mango in the frypan until the sausage is completely browned, 5 to 7 minutes. Stir in tomato puree and about half the Cheddar cheese; heat until the cheese is melted. Season with salt and pepper. Stir in cooked spaghetti. Transfer mixture to the prepared baking dish. Top with remaining Cheddar cheese.
Bake in preheated oven until the Cheddar cheese is hot and bubbly, about 30 minutes.