I adore spinach. It's one of my favorite greens. I especially love it with really browned garlic and onions. In a hot pan with extra virgin olive oil brown a large diced onion.
Add an entire head of minced fresh garlic when the onions are not quite done but are pretty golden. At this time I add my salt and white or black pepper.
When you have found that your onions and garlic are well caramelized toss in your clean, whole leaf spinach. Occasionally give it a good stir. The spinach will shrink and all the water will release, don't be afraid if the pot looks overfilled you will have more than plenty of room in a few minutes.
Keep tossing it around until all the liquid is evaporated and all that is left is the spinach, olive oil, garlic and onions. Serve warm!