Step 1: Heat olive oil over medium heat. Saute onions and fennel for 10-15 minutes or until golden brown. Stir frequently. Add sausage to the pan and brown.
Step 2: Once the sausage has browned add the water and tomato sauce, increase heat and bring sauce to a boil stirring frequently. Reduce heat and let simmer for 5 minutes.
Step 3: Drop penne in boiling salted water and cook until al dente. Drain pasta in colander.
Step 4: Add pasta in with sauce and toss to coat. Add Romano cheese, toss with the pasta until melted.
Step 5: Transfer pasta to serving dish or individually plate and serve with a dollop of ricota on top.