Clean and wash the carrots and zucchini and cut them into sticks. Wash pork tenderloin, dab dry and rub with salt and pepper. Heat oil in a pan and fry the meat all around.
Fry over medium heat for about 10 minutes. Put the vegetables into little boiling salted water and steam them for 3-5 minutes. Melt butter. Mix the egg yolks, white wine and mustard powder in a bowl and whip until thick and frothy on a hot water bath.
Whip the butter into the mixture bit by bit. Season to taste with mustard, salt and pepper. Leave the meat to rest for a while and cut open. Drain the vegetables, toss in the fat and arrange on a preheated plate with the meat and some sauce.
Garnish with parsley. Remaining sauce extra is enough.