1. Cut veal into 1-1/4 inch (3 cm) cubes.
2. Soak veal pieces in running water for 24 hours.
3. Place veal in stockpot, cover with cold water and blanch. At the first boil, strain the meat and rinse well in cold water.
4. Return to the stockpot with the carrot, leek, celery, clove studded onion and bouquet garni. Cover with white veal stock. Bring to a boil, skim and simmer over low heat for about 1 hour. Remove veal and set aside covered with a wet cloth.
5. Strain cooking liquid through a fine sieve and keep aside.
6. Prepare the roux: melt butter in a saucepan, add flour and stir until combined and frothy, remove from heat and allow to cool slightly. Gradually add hot cooking liquid to the roux, whisking well. Return to the heat to cook for about 30 minutes.
7. Add half the cream and leave to cook for another 15 minutes. Strain the sauce then add the meat and leave to simmer.
8. Cook pearl onions without coloring: peel the onions and place in a small saucepan with a knob of butter, a pinch of salt and sugar and enough water to cover them. Gently cook for about 10 minutes. Remove the onions and set aside.
9. Cook the mushrooms: cut mushrooms into quarters, place into saucepan with a knob of butter, lemon juice, a pinch of salt and water to cover. Bring to a boil, simmer for about 5 minutes. Drain and set aside.
10. Prepare garnish: potatoes can be turned in a variety of sizes. "Pommes anglaises" are turned 5 to 6 cm in length and have 7 facets. Place turned potatoes in a saucepan with a pinch of salt, cover with cold water, bring to a boil, simmer for 12 to 15 minutes.
11. Make parsley butter: bring a tablespoon each of lemon juice and water to a boil in a small saucepan. Remove from the heat, add butter, whisking well without allowing butter to boil. At the last minute, add chopped parsley and potatoes.
Finish and Presentation: remove veal from the sauce and place on a platter. Combine egg yolks and remaining cream in a small bowl, whisk in some of the sauce. Pour into the remaining sauce, whisking constantly. Strain sauce over the veal. Reheat onions and mushrooms, arrange on top. Arrange potatoes around the edge of the platter.