Bring a large pot of salted water to a boil over high heat. Add the pasta and cook until tender but still firm to the bite, stirring occasionally, about 8 to 10 minutes if dry or according to package directions if fresh. Drain pasta reserving 1 cup of the pasta cooking water.
Meanwhile, in a large, heavy skillet heat the olive oil and garlic over medium-high heat and add the sausage. Use a wooden spoon to break up the sausage into bite-sized bits. When the sausage has browned, about 5 minutes. Remove and set aside. Add the peas to the pan and, using the back of the wooden spoon, smash the peas. Turn off the heat. Add the ricotta cheese along with the cooked pasta and toss to coat, adding the pasta cooking water in 1/4 cup additions, if needed, to make the pasta moist. Return the sausage to the pan. Add the basil, Pecorino Romano cheese, and salt. Toss gently to coat and serve immediately.