In a pot on medium high heat, bring water to a boil. Once the water has boiled, add the salt and pasta. Cook the pasta for approximately 14 minutes (or until cooked).

In the meantime while the pasta cooks, grate one onion and dice the other one. Thinly slice the garlic.

On medium heat in a large pan or wok, add the butter and let it melt (if using, optional otherwise miss butter step out and jump to *olive oil). When butter has almost dissolved, add the extra virgin olive oil. If not using butter add *more extra virgin oil. Stir to incorporate the butter and olive oil together for about 30 seconds.

Add the diced onions and sauté until soft and translucent. Now add the garlic and stir. If using cherry tomatoes, add it now. Cook until tomatoes are soft and bursting in the pan.

With a slotted spoon incorporate the penne into the sauce, add a ladle of the pasta liquid (to help loosen the pasta), drizzle with olive oil and season with black pepper (optional). Thoroughly mix and coat all of pasta and sauce together.

Transfer the pasta onto a serving bowl and grate parmesan cheese over the top. Add 2 basil leaves (optional) on top as garnish. Serve and eat immediately while hot.