Preheat oven to 350 degrees F. Combine the first 6 ingredients in a bowl. Lay a piece of rouladen on a work surface, brush top side lightly with Dijon mustard. Arrange 1/8 of the vegetable mixture at one end of the rouladen; roll into a cylinder and secure with string or a toothpick. Repeat with remaining rouladen and vegetables.
Heat the oil in large skillet over medium-high heat. Brown the rouladen on all sides and then transfer to a casserole. Remove excess oil from skillet, and then add the stock/flour mixture and bring, whisking occasionally, to a boil. Pour this mixture over the rouladen. Cover and bake 60-75 minutes, or until the meat is tender. Divide rouladen among plates; sprinkle with parsley and serve.
Note: Rouladen are thin, long slices of beef sold in our meat department; they are perfect for stuffing and rolling.