Preheat the oven to 375℉.
To make the tomato sauce, heat the olive oil in a saucepan over medium heat. Add the garlic, and saute, stirring, until fragrant, about 1 minute. Lower the heat and carefully add the crushed tomatoes, tomato sauce, oregano, ¾ teaspoon of the kosher salt, and several grinds of black pepper. Simmer on low heat while making the rest of the recipe, for at least 15 minutes.
Bring a large pot of salted water to a boil. Boil the lasagna noodles, stirring often, until just before al dente, then drain. Drizzle a baking sheet with a bit of olive oil. Lay each noodle flat on the sheet, turning them over to coat with the oil.
Squeeze all of the moisture out of the thawed spinach with your hands. In a medium bowl, mix the artichokes and spinach with the sour cream, the mozzarella (or other cheese, if using), ½ cup of the Parmesan cheese, garlic powder, remaining 1 teaspoon of kosher salt and several grinds of black pepper. Stir until fully combined.
In a 9x13-inch baking dish, spread ½ cup of the hot tomato sauce over the bottom. Top with a layer of noodles, half of the artichoke filling, and 1 cup of tomato sauce, then repeat for another layer of noodles, remaining half of the spinach artichoke filling, and 1 cup more of the tomato sauce. Top with the remaining noodles and remaining tomato sauce. Sprinkle the top with the whole milk mozzarella and the remaining ¼ cup of Parmesan cheese.
Cover the pan with aluminum foil and bake for 30 minutes. Carefully remove the foil and bake until bubbly and golden brown on top, another 20 to 25 minutes. Let stand for 15 minutes before serving (this sets the texture). Garnish with chopped parsley, if desired. Cut into pieces, and serve.