Peel and wash the potatoes and, depending on their size, cut them into quarters lengthwise or into very thick sticks. Peel carrots and cut them into thick sticks. Wash and clean the zucchini and also cut them into thick sticks. Mix potatoes and vegetables, season with salt and pepper. Spread evenly on a baking tray. Spray evenly with oil. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 40 minutes.
Wash the meat, dab dry and tap flat between two layers of cling film. Meanwhile peel and finely dice the onion. Clean the mushrooms and halve them according to size. Cut bacon into strips and fry until crisp in a pan without fat, remove. Add 1/2 tbsp. oil to the pan, heat up, add mushrooms and fry vigorously while turning. Add onions and fry briefly. Season with salt and pepper. Dust with flour, sweat on and gradually add milk and stock while stirring. Bring to the boil and simmer for 2-3 minutes. Add half bacon, season with salt and pepper.
In the meantime heat 1 tablespoon of oil in a second pan. Fry the meat for about 2 minutes on each side. Season with salt and pepper. Wash thyme, shake dry, pluck leaves from the stalks. Remove the roasted vegetable fries from the oven. Arrange meat with mushroom sauce, remaining bacon and roasted vegetable fries on portion plates sprinkled with thyme.