Preheat the oven to 350°F (175°C).

In a mixing bowl, combine the crushed pineapple (drained), sugar, and shredded cheddar cheese.

Pour the mixture into a baking dish.

In another bowl, combine the crushed Ritz crackers and melted butter. Mix well.

Sprinkle the cracker mixture evenly over the pineapple layer.

Bake for 30 minutes or until the topping is golden brown.

Serve warm.