In a large pot, cook the pasta in salted water. Drain and set aside when done.
Toast the walnuts in a skillet over medium heat until just fragrant. Stir occasionally to prevent burning. Remove from heat when done.
While the pasta is cooking, make the pesto. Combine the spinach, walnuts, artichoke, lemon juice, garlic, Parmesan, red pepper flakes, oil, and salt in a food processor. Blend until you reach your desired consistency (I like mine just slightly chunky).
If the sauce is too thick, add some additional water a little at a time. Season to taste with additional salt, lemon, red pepper, or Parmesan as needed.
Toss the pasta with the pesto. Stir in some additional chopped artichokes or vegetables as desired (tomatoes, asparagus, chicken, etc). Serve warm.