Spread the flour on a small plate. Put the oil and 1tablespoon of the butter in a large skillet and place over medium-high heat. While the oil and butter are heating, coat with the flour as many slices of veal as will comfortably fit in the pan, shaking off the excess. Do not coat all the veal at once or it will become soggy.
When the oil and butter are hot and the butter is just beginning to turn color, put in as many scaloppine as will comfortably fit. When they have lightly browned on both sides and lost their pink raw color, less than 1 minute per side, remove them, letting the excess oil drip back into the skillet. Set them aside on a platter. Flour and cook the remaining veal in the same manner. If the pan becomes too dry, add a little more oil when the pan is empty and let it get hot before continuing. When all the scaloppine are done, season them with salt and pepper.
If there is more than a coating of oil left in the pan, pour it out. Raise the heat to high and add the Marsala. Pour in any juices that the meat on the platter has released. Use a wooden spoon to loosen the browned bits on the bottom of the skillet and let the Marsala bubble away until it is reduced and thickened, 1 to 2 minutes. Add the remaining 1tablespoon butter and remove the pan from the heat. Stir the butter into the sauce. Return the scaloppine to the pan and turn them in the sauce to heat them through. Serve at once.