Heat the oil in a large skillet over moderately-high heat until hot but not smoking. Add the ground turkey and, using a wooden spoon, break up the clumps and cook until golden brown, 4 to 5 minutes. Season with salt and pepper. Add the stock and scrape up any bits on the bottom of the pan. Bring up to a boil, and then let simmer until slightly reduced, about 10 minutes. Stir in the spinach and cannellini beans and heat through. Season with salt and pepper. Serve over brown rice or your favorite pasta.