Take the tenderloin out of the fridge in advance so it is not very cold.
Preheat the oven to 350 ℉ (180 ℃) with convection (fan).
Pat the meat with a paper towel to dry its surface, then season it with salt and pepper.
Add 2 tbsp of olive oil to a hot frying pan and sear the tenderloin. Make sure to sear all the sides and both ends.
Transfer the tenderloin to a baking dish and put in the oven. Bake it for 15-20 minutes or until it reaches 150℉ (or 65℃) inside temperature.
While the tenderloin is in the oven, make the sauce. Add a tbsp of the butter to the skillet where you seared the tenderloin. Finely chop two garlic cloves and fry them in the butter for 30 seconds at medium heat. Then add the chicken broth, cream, both types of mustard, and a bit of salt.
Let the sauce reduce for 10 minutes at medium heat. Mix it often.
When the tenderloin is ready, take it out and leave it to rest for 5 minutes. Then cut it in 0.8 inch slices, plate it, pour some mustard sauce on top and garnish with fresh parsley. Serve with rice and salad.
