Preheat your oven to 400°F (200°C) and lightly spray a baking dish with nonstick cooking spray.
Pat the beef tenderloin dry using paper towels. Rub all sides generously with salt, pepper, and Dijon mustard.
Heat olive oil in an oven-safe skillet over medium-high heat. Carefully place the seasoned beef in the skillet and sear it on all sides until golden brown, about 3-4 minutes per side.
Transfer the skillet directly into your preheated oven. Roast for about 15-20 minutes until the internal temperature reaches 145°F (63°C).
Let the beef rest while you prepare the sauce in the same skillet. Sauté minced garlic until fragrant, then pour in chicken broth while scraping up browned bits from the bottom of the pan. Stir in heavy cream and any remaining Dijon mustard.
Slice the rested beef into medallions and plate them beautifully, drizzling the sauce over each piece.