01 -  Set oven to 400°F (200°C) and allow to fully preheat. 
 02 -  Place feta cheese block in the center of a medium baking dish. 
 03 -  Arrange cherry tomatoes, minced garlic, and sliced red onion (if using) evenly around the feta. Drizzle with olive oil, sprinkle with dried oregano, red pepper flakes, salt, and pepper. Toss tomatoes gently to coat. 
 04 -  Bake uncovered for 20 minutes, until tomatoes burst and feta is golden and softened. 
 05 -  Boil the pasta in salted water according to its package instructions until al dente. Reserve 1/2 cup pasta water and drain pasta. 
 06 -  Remove the baking dish from the oven. Mash roasted feta and tomatoes together with a fork until creamy. 
 07 -  Add cooked pasta and chopped basil to the baking dish. Toss to combine, adding reserved pasta water gradually for desired sauce consistency. 
 08 -  Plate hot and top with additional fresh basil for garnish.