Preheat the oven to 400°F (200°C).

In a small skillet over medium heat, toast the sesame seeds until golden brown, about 3-4 minutes, stirring frequently to prevent burning. Remove from heat and let cool.

In a small bowl, combine the toasted sesame seeds, crushed red pepper flakes, salt, and black pepper. Mix well.

Rub the veal tenderloin with olive oil, then coat it evenly with the sesame-crushed red pepper mixture, pressing gently to adhere.

Heat a large oven-safe skillet over medium-high heat. Add the veal tenderloin and sear on all sides until browned, about 3-4 minutes per side.

Transfer the skillet to the preheated oven and roast the veal for 15-20 minutes, or until it reaches an internal temperature of 145°F (63°C). Remove from the oven and let it rest for 10 minutes before slicing.

While the veal rests, prepare the gravy. In the same skillet used for the veal, add the butter and the white parts of the chopped scallions over medium heat. Sauté until the scallions are softened, about 2-3 minutes.

Pour in the beef broth and soy sauce, scraping up any browned bits from the bottom of the skillet. Bring to a simmer and let cook for 5-7 minutes to reduce slightly.

If you prefer a thicker gravy, stir in the cornstarch mixture and cook for an additional 2 minutes until thickened.

Slice the rested veal tenderloin into medallions and serve drizzled with the scallion gravy, garnished with the green parts of the scallions.