Bring a large pot to a boil. Add 3 tablespoons salt. Once the water starts to boil, add in the pasta. Cook until Cavatappi is al dente. Drain and set aside the pasta. Add 1 tablespoon butter and a sprinkle of parmesan on top.
In a pan, add about 2 tablespoons of olive oil. Once hot, add the onions and scallions. Then add the chopped garlic and saute until translucent.Then add 4-5 cups chopped baby spinach and the chopped dill. Add the ground cumin, salt and pepper. Add the lemon juice and stir. Now add the cooked Cavatappi pasta in and combine everything. Turn the heat off. Crumble the Feta cheese and ¼ cup parmesan and it to the mixture. Serve hot or at room temperature.