Wash the fillet, dab dry and cut into strips. Dice onion. Wash and finely dice the carrot. Wash and halve or quarter the mushrooms. Wash the thyme, dab off the leaves.
Heat oil in a small pan. Fry the meat for 2-3 minutes all around. Season and take out. Sauté the onion, mushrooms and carrot in the cooking fat for about 2 minutes. Meanwhile cook the pasta in plenty of boiling salted water for about 10 minutes until al dente. Deglaze vegetables with about 1/8 litre water, bring to the boil and stir in stock. Simmer at medium heat for about 3 minutes. Add meat again. Thicken sauce, refine with cream, season to taste.
Deglaze vegetables with about 1/8 litre water, bring to the boil and stir in stock. Simmer at medium heat for about 3 minutes. Add meat again. Thicken sauce, refine with cream, season to taste. Drain pasta well and arrange on a plate with the sliced meat. Garnish with parsley if desired.