Bring a large pot of water to a boil over medium-high heat.
Use a sharp knife to cut a shallow X-mark on the bottom (the opposite side of where the stem would be) of each tomato.
When the water starts to boil carefully lower the tomatoes in the boiling water.
Boil the tomatoes for 1 to 2 minutes or until you see the skin of tomatoes beginning to peel.
Rinse the tomatoes under cold water until cool enough to handle then use your fingers to pull the skins off the tomatoes.
Discard the skins then roughly chop the tomatoes and set aside.
Heat the oil in a dutch oven over medium-high heat.
Add the ground beef to the dutch oven and cook, while breaking up the beef with a spatula, until browned, about 5 minutes.
Add the onion, tomatoes, garlic, oregano, basil, crushed red pepper, 2 tsp salt, and 1/2 cup water to the dutch oven and bring to a boil.
Reduce the heat to medium-low then place a lid on the dutch oven and simmer the sauce, occasionally stirring and breaking up the tomatoes with a spatula, for about 30 minutes.
Remove the lid from the dutch oven and continue to simmer the sauce without the lid, stirring occasionally, until thickened, about 1 hour and 30 minutes.
Take the dutch oven off the heat then taste and season the sauce with additional salt & pepper if needed.