This was one of those dishes where I had a recipe, and then I decided to improvise some ingredients. Then some more, and then ended up with something completely different. However, it was really, really, good in my own extremely humble opinion, ahem.  

Bring large pot of salted water to a boil and cook pasta according to instructions on the box. In a large skillet, heat up the oil and add the sausage. Add the red pepper flakes and cook until it starts to turn a little brown. Add the onion and garlic, and cook until onion softens. Add the tomatoes, feta, and yogurt and stir well. Pasta will be thick. Drain the noodles and add pasta mix & basil & serve.