Fill one pot with 8 cups of water and one tablespoon of salt, dissolve the salt in the water, set it aside.
In a large dutch oven (or another pot), cook the diced onions in the virgin olive oil at medium-high heat until they become soft and semi-translucent. Season with salt and pepper.
[optional] Add the ground beef, breaking it up into small pieces and brown thoroughly (you shouldn’t be able to see any pink meat).
Add the garlic, strirring often, cook for 2 more minutes.
Add the tomatoes, mixing it all together. If they are pre-diced, then crush them with a patato masher or your spatula. Depending on the consistency of the canned tomato juice, you might want to add half a cup of water to the sauce to make it a bit less thick.
Add the italian seasoning (3-4 tablespoons should be enough), mix. As a rule of thumb, you can cover the surface of the sauce with a thin layer of seasoning.
Bring it to a boil over high heat.
Once boiling, reduce heat to low-medium. Simmer uncovered, stirring occasionally, until sauce reaches the desired consistency (thicker than soup but thinner than yogurt or chili).
Taste and adjust the seasoning as the sauce thickens.
As the sauce thickens, bring the pot of water we set aside earlier to a boil. Then, add 2 cups of penne per person to the pot. Set a timer!
For two minutes or so, move the noodles around so that they don’t stick to the bottom of the pot.
When the noodles are ready (look at the packaging for the exact time or taste them as you go), drain them, put them back in the pot and remove from the stove.
When the sauce is ready, add 1/2 cup of butter to it and mix until its fully dissolved.
Add 1-2 cup(s) of sauce per person being served to the noodles. Mix the noodles and the sauce together.
Serve the sauced noodles in small to medium sized bowls, top the noodles with more sauce and grated parmesan cheese.
Any leftover sauce can be frozen in pyrex containers or plastic freezer bags. Eat within 3+ months ideally. Any leftover noodles can be stored in the fridge for a few days but freshly cooked noodles are always better.