This is a quick and easy dinner if you have the tomatoes ready ahead of time.
Roast the tomatoes: Preheat oven to 350 degrees. Halve 5 plum tomatoes. On two large rimmed baking sheets, arrange tomatoes, cut side up, and sprinkle with sugar. Bake until softened and edges are crinkled, about 1 hour. Let cool.
Set a large pot of salted water to boil. Meanwhile, in a bowl, combine tomatoes, oil, capers (if using), and lemon juice; season with salt and pepper. Cook pasta until al dente. Drain pasta and return to pot; toss with tomato mixture. Serve pasta topped with basil.