Season the meat well with salt and pepper and let it rest for approximately 30 minutes at room temperature.

Heat a large pan or skillet and sear the meat well on both sides in the oil. Allow it to develop a crust before turning, as too much turning will cool the pan and make it difficult for the meat to achieve a good crust.

Place the meat in an ovenproof dish. Add lemon slices, thyme, and whole garlic cloves to the meat. Place the dish in a preheated oven at 200 degrees Celsius (392 degrees Fahrenheit) for 15 minutes.

Remove the roast from the oven and cover it with a clean kitchen towel. Let it rest for 15 minutes to keep the juices inside the meat.

Take the butter out of the refrigerator and let it reach room temperature.

Rinse and finely chop the parsley and press the garlic.

Mix soft butter, pressed garlic, Dijon mustard, and finely chopped parsley together. Season with salt and pepper.

Place the butter in the refrigerator.

Take it out approximately 30 minutes before serving.

Slice the chili into thin slices and remove the seeds.

Peel the shallots and garlic. Finely chop the shallots and slice the garlic thinly.

Clean the leeks and slice them thinly.

Rinse the pears, leaving the skin on.

Remove the cores.

Clean the mushrooms and slice both them and the pears.

Rinse the tarragon and chop it finely.

Heat butter and oil in a large pan and fry the vegetables over medium heat until they take on a bit of color.

Add finely chopped tarragon and continue to fry for 5-7 minutes, depending on how crisp you want the vegetables.

Season with salt and pepper.

Slice the meat and serve it with sautéed vegetables, garlic butter, and optionally boiled or baked potatoes.