Cook pasta in salted boiling water until al dente, then drain.
Heat olive oil in a large skillet over medium heat.
Add minced garlic and red pepper flakes; sauté for 1 minute until fragrant.
Pour in diced tomatoes and oregano, simmer for 5 minutes.
Stir in fresh spinach and cook until wilted, about 2 minutes.
Season sauce with salt and black pepper.
Add cooked pasta to the skillet and toss to coat with sauce.
Remove from heat, sprinkle with Parmesan cheese, and garnish with basil leaves.
Serve warm.