First, take the slices of turkey breast and cut them into long strips 1 to 2 inches wide and at least 5 to 6 inches long--sort of like turkey bacon. Leftover turkey tends to go dry, so moisten them up by putting them in a steamer for about 5 minutes. This will make them easier to roll without cracking. In the meantime, heat up the spinach in the microwave.
Once the strips of turkey are steamed, smear each one with spoonful of spinach--enough to put a thin, even layer on top of each. Then, simply roll each piece, and trim the sides with a knife so you get a nice clean cut. Transfer the gravy into a squeeze bottle and garnish.