Bring a large pot of water to a boil, salt it, add the pasta and cook until al dente. Drain, reserving the pot.
While the pasta is working, in a medium skillet, heat the EVOO, 8 turns of the pan, over medium heat. Add the capers and fry until they open, 3 to 4 minutes. Using a slotted spoon, transfer to paper towels to drain. Add the garlic to the skillet and cook until lightly golden, 1 to 2 minutes. Add the spinach and cook until wilted, 1 minute.
In the pasta pot, whisk the ricotta and milk over low heat until warmed through, 2 to 3 minutes. Season with the thyme, some pepper and the nutmeg, if using. Add the pasta and toss to coat.
Discard the garlic and stir the spinach into the pasta. If desired, add some of the spinach oil from the skillet. Top with the fried capers.