In a large pot, bring a generous amount of salted water to a rolling boil. Add the pasta and cook according to the package instructions until it reaches an al dente texture. Once cooked, reserve 1 cup of the pasta water, then drain the remaining water and set the pasta aside.
In a large skillet, heat the extra virgin olive oil over medium heat. Once hot, add the minced garlic and diced onion. Sauté for about 2-3 minutes until the garlic is fragrant and the onion becomes translucent. Stir frequently to prevent burning.
Pour in the can of diced tomatoes along with their juices. Stir to combine, then season with dried oregano, red pepper flakes, salt, and cracked black pepper. Allow the mixture to simmer gently for about 5 minutes, letting the flavors meld together. Next, add the chopped fresh spinach, cooking for an additional 2-3 minutes or until the spinach has wilted.
Add the drained pasta directly into the skillet with the tomato and spinach mixture. Toss everything together thoroughly, incorporating the reserved pasta water a little at a time until you achieve your desired sauce consistency.
Transfer the garlicky spinach tomato pasta to serving plates or a large bowl. Garnish each serving with fresh basil leaves. For an extra touch of flavor, sprinkle with grated Parmesan cheese to taste before serving.
Notes
Serve with a drizzle of olive oil and extra Parmesan for enhanced flavor.