Heat olive oil in a large oven-safe skillet over high heat. Sear the pork loin filet until lightly golden all over, approximately 5 minutes total.
Transfer skillet to the oven and roast the pork for 12-14 mins, or until the thickest part reaches 145º F.
Once cooked, remove the pork from the skillet and allow to rest.
Add garlic and rosemary to the skillet and sauté over medium high heat for one minute, until fragrant.
Add in the chicken stock and use your wooden spoon to scrape off any pork bits from the skillet.
Allow the stock to reduce by half. Pour in cream and stir in dijon. Siimmer until the sauce starts to thicken, approximately 2 - 3 minutes.
Taste and season with salt and pepper as desired.
Slice pork and drizzle with the mustard sauce. Serve and enjoy!