Place a large pot of salted water over high heat and bring it to a boil.
Once the water boils, cook the cavatappi to al dente according to package directions. Once the pasta has finished cooking, drain it and return it to the pot it was cooked in.
While the pasta is cooking, place a large skillet over medium-high heat with 2 turns of the pan of EVOO, about 2 tablespoons. Add the onions to the pan and top them with a lid or piece of aluminum foil for 2-3 minutes, just to get them cooking. Remove the lid or aluminum foil and continue cooking the onions until tender and lightly caramelized, 8-10 minutes.