- 1/4 cup plus 6 tablespoons extra-virgin olive oil
- 1 Vidalia (or other sweet) onion, finely sliced
- 9 to 10 fresh plum tomatoes sliced into 1/3-inch thick rounds
- Salt and freshly ground pepper
- 2 cloves garlic, pressed through a garlic press, or 1/2 teaspoon garlic powder
- 2 1/2 tablespoons finely grated Parmesan cheese, plus extra for serving
- 2 1/2 tablespoons finely grated pecorino cheese
Preheat the oven to 400° and center a rack in the oven.
Spread 1/4 cup of the olive oil on a 13x17” rimmed baking sheet. Scatter the onion slices evenly over the sheet in a single layer. Arrange the tomato slices side by side over the onions so that the entire sheet is evenly covered.
Push the slices right up against each other without overlapping them. Sprinkle with about 1/4 teaspoon salt and 1/8 teaspoon pepper. If using fresh garlic, squeeze it through a press onto the cutting board (not directly onto the tomatoes—you don't want it all to land on one lone tomato). Sprinkle the pressed garlic or garlic salt, if using it, evenly over the tomatoes. Sprinkle the Parmesan so that each tomato slice gets a light covering and then do the same with the pecorino. Drizzle all over with 2 more tablespoons olive oil.
Roast until the edges of the tomatoes are shriveled (some will begin to brown) but the tomato slices themselves have not yet begun to brown, 50 to 60 minutes. (At this point, you can cover the baking sheet with foil and set it aside at room temperature until you're ready to eat; the heat of the just-cooked pasta will rewarm the vegetables.)
For the rigatoni, bring a large pot of water to a boil. Add salt until the water tastes salty (about 1/4 cup). Set a colander in the sink. Add the pasta and cook according to the package directions. Drain in the colander. Return the rigatoni to the pot. Scrape in the tomato-onion mixture, add the remaining 1/4 cup olive oil, and stir well. Divide it among bowls or plates. Add a little pepper to each, and serve with more Parmesan cheese.