Preheat the oven to 350 degrees F. Lay a piece of rouladen on a work surface; season with salt and pepper. Sprinkle with 1/8 of the cheese; top with 1/8 of the spinach. Roll into a tight cylinder and secure with string or a toothpick.
Repeat these steps with the remaining rouladen. Heat the oil in large skillet set over medium-high. Brown the rouladen on all sides and then transfer to a casserole. Remove the excess oil from skillet; add the pasta sauce and bring to a boil. Pour this mixture over the rouladen. Cover and bake for 60 to 75 minutes, or until the meat is tender. Divide rouladen among plates, spoon the sauce over them and serve.
Note: Rouladen are long, thin slices of beef that are great for stuffing and rolling. You'll find them in our meat department.