Prep the Steak:
Let the flank steak come to room temperature for 30 to 60 minutes. Place between parchment paper and pound to an even thickness of about 1/2 inch. Trim to a rectangular shape if necessary.

Season the Steak:
Combine all dry rub ingredients in a small bowl. Sprinkle and rub generously over both sides of the steak. Place three pieces of cooking twine under the steak and set aside.

Prepare the Filling:
In a medium bowl, mix together garlic, diced red pepper, sun-dried tomatoes, chopped basil, spinach, egg yolk, breadcrumbs, and shredded mozzarella until well combined.

Stuff and Roll:
Spread the filling evenly down the center of the steak, following the grain, leaving about 1 inch from the edges. Carefully roll the steak up like a jelly roll and tie with the pre-placed twine.

Roast:
Preheat oven to 425°F. Brush a cast iron skillet or oven-safe pan with 1 tablespoon olive oil. Place the rolled steak seam-side down in the pan, drizzle with another tablespoon of olive oil, and roast for 25 minutes.

Add Asparagus & Broil:
Toss asparagus with the remaining 1 tablespoon of olive oil. After 25 minutes of roasting, add asparagus to the pan, sprinkle with sea salt, and switch the oven to broil. Broil for 10 minutes, until asparagus is slightly charred and steak is crisp on top.

Rest and Serve:
Remove from oven, loosely tent with foil, and let rest for 10 minutes before slicing. Ensure the internal temperature reaches 130°F for medium after resting. Slice and serve warm with the roasted asparagus and any pan juices.