In a large pot, bring 4 quarts of water and 1 tablespoon of kosher salt to a boil. Grease a 9 x 13-inch baking dish with 1 tablespoon of extra-virgin olive oil.
Using a food processor, purée two 28-ounce canswhole tomatoes. Once puréed, set aside.
Halve and thinly slice 2 yellow onions. In a large pot over medium-high heat, heat 2 tablespoons of extra-virgin olive oil. Once the oil shimmers, add the sliced onions, and cook over medium heat until browned, about 5-6 minutes.
Meanwhile, mince 2 cloves of garlic and cook with the onions until fragrant, only about 15 seconds. Carefully add in the puréed tomatoes, ¼ cup of pasteurized heavy cream, and ½ teaspoon of kosher salt. Stir in cautiously as these ingredients like to splatter! Bring to a boil and then reduce the sauce to a simmer for about 10 minutes, stirring occasionally, until it thickens.
Thoroughly wash a small handful of fresh flat-leaf parsleyunder cool, running, drinkable water. Chop ¼ cup and add to the pot.
Add ½ teaspoon of crushed red pepper flakes and cook another 2-3 minutes. Add kosher salt and freshly ground black pepper to taste and remove from heat.
Once the salted water comes to a boil, cook 1 pound of rigatoni pasta until al dente, about 10-12 minutes. Once at the desired texture, instead of using a strainer to drain the pasta, use a large slotted spoon to transfer the cooked pasta to the sauce pot.
Bring the water back to a boil and add 1 pound of small cauliflower florets. Cook until barely tender, about 2 minutes. Using a strainer, drain the cauliflower and add it to the pasta pot.
Add ¾ cup of shredded pasteurized mozzarella to the pasta and toss. Transfer the pasta to the prepared baking dish and spread evenly.
Top the pasta with the remaining ¾ cup of shredded pasteurized mozzarella and ¾ cup of grated Parmigiano-Reggiano.
Bake uncovered until the cheese is golden brown, about 15 minutes. Allow the pasta to cool for a few minutes before serving. Eat up, Mama!
Once cooled completely, store leftovers in the fridge. Once firm enough to slice, portion out servings into airtight plastic baggies for the freezer. Your future self will thank you kindly.