Preheat oven to 375°F (190°C). Lightly butter a 9×13-inch baking dish.

Bring a large pot of salted water to a boil. Cook penne for 6 minutes—about 2 minutes shy of package directions—then drain thoroughly.

Return pasta to the pot over low heat. Stir in butter until melted. Remove from heat and fold in 1¾ cups of the cheddar, drained tomatoes, sugar, and salt until evenly coated.

Transfer mixture to the prepared dish. Sprinkle remaining cheese on top and tent with foil.

Bake covered for 30 minutes. Remove foil and bake 10–15 minutes more, until cheese is bubbly and golden. Let rest 5 minutes before serving.