Cook the bacon in a large skillet over medium heat until crisp. Drain onto a paper towel. If desired, remove some of the bacon fat. To the skillet, add the butter, lemon slices, thyme, garlic, and orzo. Cook until the orzo is toasted, 2 minutes. Add 3 cups water and the spinach. Season with salt and pepper. Cook 5 minutes, until the orzo is al dente and most of the liquid has evaporated, but not all of it. Whisk together the eggs and parmesan in a bowl.Remove the orzo from the heat. Add the egg/cheese mixture, tossing quickly (to ensure the eggs do not scramble) until the eggs thicken and create a sauce. Add the basil and season with salt and pepper.Serve the carbonara with grated parmesan and bacon. Drizzle a bit of olive oil or melted butter over top. Enjoy!