Cook the spaghetti according to package directions.
Meanwhile, heat the butter together in a large nonstick skillet over medium low heat. Add the minced garlic and saute for 3-5 minutes, until soft and fragrant. Be careful not to burn or over-brown the garlic because it will taste bitter. Low and slow is the winner here.
Chop the spinach and basil (I had about 5 cups total - it reduces quite a bit as it wilts) into small bite-sized pieces and add to the skillet, stirring for just a minute or two to get the greens softened slightly. Season with salt.
Add the spaghetti to the skillet (or vice versa depending on pan size) and season with salt and pepper. Toss well to combine and let it all rest for a few minutes to stick together a bit. Serve with an additional pat of butter and/or fresh grated Parmigiano Reggiano cheese.
For the leftovers, I added a can of roughly chopped fire-roasted whole tomatoes and about ½ cup of vegetable broth and simmered for an additional 10 minutes. The noodles were thick and saucy and loaded with vegetables. So good!