Wash and peel the potatoes and carrots. Halve the potatoes and slice the carrots. Let the vegetables cook in 1/2 liter of salted water for about 15-20 minutes. Drain the vegetables, collecting 1/4 liter of the cooking water.
Melt the fat, sweat the flour in it. Deglaze with the vegetable water and milk while stirring, sprinkle with the stock. Let simmer for about 5 minutes. Wash and chop parsley. Put the potatoes, carrots and parsley in the sauce and heat them up.
In the meantime, heat the oil, fry the schnitzel on both sides for 5 minutes, season.
Season the vegetables with salt and pepper and serve with the schnitzel.