Cook pasta in a large pot according to package directions until al dente, drain.  Meanwhile, in a large skillet, heat the olive oil,  Add the leek and ham and cook until softened.  Mix arrowroot into cream substitute.  Pour into pan and stir until slightly thickened, about 3-5 minutes.  Add the spinach and cook until wilted.  Combine the pasta and the sauce and toss with basil and salt and pepper to taste.