Start by dicing the onion and mincing the garlic.
Preheat a large skillet (10") over medium-high heat. When the pan is hot, add the olive oil along with the onion and garlic. Lower the heat to low or medium-low and cook until the onion softens about 3-5 minutes.
Blend the diced tomatoes in a blender until mostly smooth. Pour the blended tomatoes into the skillet and add the tomato paste.
Mix together until smooth, then add the heavy cream and stir to combine again. Bring the sauce to a simmer, and cook until the flavors meld and the sauce has thickened 8-10 minutes. Stir as little as possible so the liquid layer on the top is undisturbed, it helps to prevent splattering.
When the sauce is done, season to taste with sea salt and pepper. Stir in half of the parmesan cheese then sprinkle the remaining amount over the top and garnish with chopped fresh parsley or basil.
Serve this sauce with your choice of protein or freshly cooked pasta.
