Defrost the spinach in the microwave, wring it dry and separate the leaves.
Meanwhile, bring a large pot of water to a boil, salt it, add the tortellini and cook according to package directions. Drain and let cool.
In a large skillet, heat the EVOO, 2 turns of the pan, and butter over medium heat. Add the shallot and garlic and cook, stirring, for 2 minutes. Add the artichokes and spinach; season with a little salt and pepper and a hint of freshly grated nutmeg.
Add the tuna and pasta to a bowl. Top with the spinach and artichokes. Dress with the lemon juice and thyme. Serve or refrigerate for later.