01 - Preheat oven to 400°F.
02 - In a large ovenproof baking dish, combine cherry tomatoes, sun-dried tomatoes, garlic, and 2 tbsp olive oil. Season generously with salt, black pepper, oregano, and red pepper flakes if desired. Toss thoroughly.
03 - Place the feta block in the center of vegetables, nestling it among the tomatoes. Drizzle with 1 tbsp olive oil and season with a touch of black pepper.
04 - Bake for 25 to 30 minutes, until tomatoes are bursting and feta is golden and softened.
05 - Meanwhile, heat a large skillet over medium and add 1 tbsp olive oil with sliced onions. Sauté, stirring occasionally, for 15 to 20 minutes until deeply caramelized and golden brown. Set aside.
06 - While onions cook, boil pasta in salted water according to package instructions until al dente. Reserve 1/2 cup pasta water, then drain.
07 - Remove baking dish from oven. Add caramelized onions and chopped basil. Stir thoroughly, breaking down the feta to form a creamy sauce.
08 - Add the cooked pasta to the dish and toss well to ensure even coating. For added creaminess, mix in reserved pasta water gradually to achieve desired sauce consistency.
09 - Serve immediately, garnished with additional basil and a drizzle of olive oil as preferred.