Rub roast pork with salt and pepper. Clean and roughly chop the soup greens. Cut the onion into wedges. Wash, quarter and core apples, also cut into wedges.
Heat the oil in a roasting pan, fry the meat all over. Add the prepared ingredients and sauté. Mix 1/8 liter each of apple juice and broth with 2 tablespoons of mustard, pour in.
Cook the roast in the preheated oven (electric stove: 200 degrees, gas: level 3) for about 1 1/4 hours. Gradually pour in the rest of the stock and juice. Scoop the roast with it from time to time.
Peel the carrots and cut into sticks. Cook in boiling salted water for approx. 12 minutes. Clean zucchini, cut into pieces and add to the carrots about 5 minutes before the end of the cooking time.
Take the roast out of the roaster. Strain the meat stock through a sieve. If necessary, fill up to 1/2 liter with water. Bring the stock to the boil. Mix the flour and cream until smooth, stir into the stock, bring to the boil and simmer for 5 minutes. Season the sauce with the remaining mustard, salt and pepper. Chop the tarragon and stir into the sauce.
Heat the butter. Toss the drained vegetables in it. Arrange everything on a plate and garnish with tarragon.