Heat oven to 375℉. Lightly oil a large baking sheet with olive oil or line it with parchment and spread 1 pint cherry tomatoes and sliced 1 red onion out in an even layer. Drizzle with 2 tablespoons of the 3 tablespoons extra virgin olive oil and sprinkle with ¼ teaspoon fine sea salt and ½ teaspoon ground pepper. Place in the oven and roast for about 25 minutes, until onion is slightly caramelized and tomatoes are soft and juicy.
While the vegetables are cooking, cook the pasta according to the package directions. Drain and place in a large bowl.
Add the cooked tomatoes and onion, the 1 cup crumbled feta cheese, and a little more olive oil if you like. Stir gently to combine, then add more salt and pepper to taste.
Serve warm or at room temperature.
Notes
Make vegetables ahead. To save time, you can roast the vegetables up to 2 days in advance and store them in an airtight container in the fridge. Rewarm for 30 seconds in the microwave before mixing them in with the cooked pasta.
A different cheese. If you don't care for feta, try a mellower cheese like burrata. For a creamier version, add ricotta cheese.
Add a splash of balsamic vinegar. To play up the sweet-tangy flavors even more, add a splash or two of balsamic vinegar to the bowl, or drizzle it over individual portions.
Vegan. Choose a vegan feta (or another vegan hard cheese of your choice) and use it in place of the feta.
More veggies. Make this into more of a vegetable feta pasta dish by adding roasted or sauteed zucchini, red pepper, mushrooms, or asparagus.