• Bring a large pot of lightly salted water to a boil. Cook pasta in boiling water until al dente; drain.
• Meanwhile, heat olive oil in a large skillet over medium- high heat; add onion and garlic, and cook until golden brown. Mix in tomatoes, mushrooms and spinach. Season with salt, pepper and red pepper flakes. Cook two minutes more, until tomatoes are heated through and spinach is wilted. Reduce heat to medium, stir in pasta, feta cheese and artichoke hearts. Cook until heated through. Toss in olives (optional).