Cook pasta using the package directions until they are just under al dente. It will finish cooking in the sauce. Reserve about ½ cup of pasta water. Drain the pasta and set aside.
While the pasta is cooking, dice the onion and mince the garlic. Preheat your skillet over medium heat, add a Tablespoon or two of olive oil, and sauce the onions and garlic until soft and fragrant. Add a pinch of salt and a little bit of pepper to the onions and garlic as they cook. This builds a layer of flavor.
Wash the cherry tomatoes and add them straight to the pan. Cook until about half of the tomatoes burst, about 10 minutes, stirring occasionally. Smush the tomatoes a little bit as they burst to deglaze the pan.
Carefully ladle the tomatoes, onions and garlic into a blender. Cover and blend for about 15 seconds. Return the sauce to the skillet. DO NOT use an immersion blender. See note.
Bring the sauce back to a simmer, and season with salt, pepper, Tony Chachere's (optional), and sugar. Sugar helps balance the acidity of the tomatoes.
Add one drained can of either cannellini or great northern beans to the sauce. Stir to combine. Return the sauce to a simmer.
Add the pasta to the simmering sauce. Stir to combine. Cover and let cook until the pasta reaches your desired doneness, probably 3 minutes or so. You can add a bit of pasta water if needed, but be careful not to dilute the sauce. Serve with grated parmesan cheese, additional halved cherry tomatoes, and parsley, if desired.