Defrost the peas. Meanwhile clean and peel the carrots. Cook whole carrots in boiling salted water for about 15 minutes. In the meantime crumble the toast finely. Prick sausages several times.
Turn one after the other in flour, whisked egg yolk and the toast bread crumbs. Fry in hot oil over medium heat for about 5 minutes, turning. For the mashed potatoes bring 1/2 litre of water and salt to the boil.
Remove the pot from the heat and add the milk. Stir in the purée flakes. Season with nutmeg. Drain the carrots and cut them into slices with a colored knife. Melt the fat and add peas and carrots.
Arrange on plates with sausage and mashed potatoes and serve garnished with parsley.