In a large pot, warm the oil over medium heat. Add the cabbage and ½ teaspoon salt and cook until softened and beginning to brown, about 5 minutes, stirring occasionally.
Add the veggies, garlic, and remaining ½ teaspoon salt and cook for 5 more minutes, stirring occasionally, or until softened.
Add the macaroni, water, and tomatoes. Use your hands or scissors to break the tomatoes open and into chunks to release their juices. Stir everything together, then cover and increase the heat to high to bring to a boil. Remove the lid and give it a stir to scrape up any pasta stuck to the bottom.
Stir to evenly distribute to pasta and make sure it’s covered by liquid, then cover and simmer over low or medium-low heat for about 15 minutes, stirring halfway through to scrape up any pasta stuck to the bottom. Be sure to taste and see if your macaroni is cooked through. If it’s not, just cover and simmer longer. If too much liquid is in your pot at the end, just simmer it uncovered to reduce. You want it nice and saucy!
Remove from heat. In a small bowl, mash up the miso with the water and then stir it into the pot along with the butter.
Serve topped with cheese (if using), black pepper, and basil (if using).