Heat olive oil in a large pot over medium heat. Add garlic and sauté for 30 seconds until fragrant. Tip: Don't let the garlic brown or it may turn bitter

Add pasta, diced tomatoes with their juices, vegetable broth, basil, and red pepper flakes (if using). Stir to combine. Tip: The liquid should just cover the pasta

Bring to a boil, then reduce heat to a simmer. Cover and cook for 12-15 minutes, stirring occasionally, until pasta is al dente and most liquid is absorbed. Tip: If pasta isn't cooked but liquid is low, add 1/4 cup water

Remove from heat. Stir in Greek yogurt until fully incorporated, then fold in spinach until wilted. Tip: Adding yogurt off heat prevents curdling

Season with salt and pepper to taste. Serve topped with Parmesan if desired. Tip: For extra creaminess, reserve 1/4 cup pasta water to adjust consistency