Place cherry tomatoes, sliced onion, and sliced garlic cloves in a baking dish or casserole.
Drizzle 1/4 cup of olive oil.
Season with kosher or sea salt,half of the freshly cracked black pepper, red pepper flakes, and half of the Italian seasoning. Give it a good mix.
Make some space in the center of the dish, place the block of feta cheese, drizzle the remaining 1/4 cup of olive oil, sprinkle the remaining black pepper and Italian seasoning.
Bake in the preheated oven for 30-35 minutes, or until the tomatoes are bursting, and the cheese is soft and melty.
While the veggies are baking, boil the pasta. Cook 2 cups of pasta as per the instructions on the pasta box. Drain, reserve about a cup of the starchy pasta water, if needed later.
Remove the baking dish from the oven.
The tomatoes would have burst open and the cheese should be soft and melty. Mash the cheese with the help of a fork or spatula, then mix everything together.
Add the cooked pasta and roughly torn basil leaves.
Toss gently until the pasta is evenly coated with the creamy sauce.
If it looks dry, add some of the reserved pasta water, a few tablespoons at a time. I didn't need to add any extra liquid.
Check for seasonings, adjust with salt and pepper if required. Dish out, serve with a sprinkling of freshly grated parmesan cheese if desired.