In a small bowl, whisk together soy sauce, oyster sauce, fish sauce, brown sugar, minced chili, and garlic to create the marinade glaze.
Lay steak strips flat and brush both sides lightly with a portion of the sauce mixture.
Place a bundle containing 3-4 Thai basil leaves, 2 strips of julienned pepper, and 2 scallion segments at one end of each steak strip.
Roll the beef tightly around the vegetable filling and secure the seam with a wooden toothpick.
Heat vegetable oil in a large skillet or wok over medium-high heat until shimmering.
Place rolls seam-side down in the skillet and sear for 2-3 minutes per side until the beef is browned and cooked through.
Pour the remaining sauce into the skillet and toss the rolls for 1 minute until the glaze has thickened and coated the beef.
Remove toothpicks before serving immediately.