Wash the herbs if necessary, spin dry and chop finely.
Slice the beef tenderloin lengthwise, starting 1 cm above the board, do not cut all the way through, fold the thick top piece back, cut another 1 cm above the board, fold the thicker top piece back again and cut. You will end up with a large flat slice of beef tenderloin.
Using a plating tool or a stockpot, pound it a little flatter still, season with salt and pepper, and coat evenly with mustard. Spread the chopped herbs over the mustard layer. Roll up the meat into an even roll and wrap tightly with kitchen twine. Season the fillet roll with salt and pepper and fry it all around in hot oil. Do not forget the two ends. Add butter, rosemary and thyme sprigs, drizzle the meat with the butter (glaze), then remove and place on a baking tray lined with aluminum foil together with the herbs. The foil may look a bit crumpled, then the heat can circulate better later.
Cook in a preheated oven at 120 °C for about 45 – 50 minutes. The roast can then rest at 70 – 80 °C without losing any of its quality. It goes very well with a celery-potato puree or sweet potato puree, both flavored with truffle butter.
Parsley root and potato puree is also delicious with this. For some time there is also aluminum foil, which is covered with baking paper on the side facing the food, this is also recommended.
