Preheat oven to 400℉
Sprinkle salt, pepper, and poultry seasoning all over the pork tenderloin
Place large saute pan or skillet over medium high heat
Add olive oil and butter to the pan. Heat until butter melts and begins to bubble
Add pork tenderloin to the pan and sear on all sides until brown. (Approximately 5-7 minutes)
Add crushed garlic cloves, wine and ¼ cup of the chicken stock to the pan
Allow liquid to bubble in pan until it reduces by half (approximately 2-3 minutes)
Cover pan and place in 400℉ oven for 20 minutes
After 20 minutes, remove pan from oven and carefully remove the lid from the pan
Remove the pork tenderloin from the pan and place on a platter. Cover with aluminum foil to keep it warm
Place the pan (with the juices and garlic cloves) over medium heat. Using a sifter, sift the flour over the pan juices and whisk well.
Slowly add the remaining chicken stock to the pan.
Cook over medium-low heat, whisking often until the sauce thickens (approximately 2-3 minutes).
Slice the pork tenderloin, pour the garlic gravy over the top, and garnish with fresh thyme leaves.