In a large stock pan over medium-high heat, add the olive oil and the onion. Allow the onion to cook until it is tender (about 3 minutes). Add the tomato (or marinara sauce) and garlic and incorporate it into the mixture. Cook for just 1-2 minutes (be careful not to burn the garlic).
Add the vegetable stock, water, salt, pepper and red pepper flakes. Bring this to a boil and then add your pasta. Lower the heat and allow the pasta to cook until it’s about 3/4 of the way finished (still slightly firm).
Add your beans and allow the mixture to continue cooking until the pasta is fully cooked (about 10-15 minutes). Add the parsley toward the end of your cooking time. Taste and adjust the seasoning as needed.
Serve in individual bowls with extra parsley as garnish and sprinkle with the Parmesan cheese.