Slice the halal beef sausage links lengthwise and sear them in a non-stick skillet over medium heat until browned and fully cooked.
While the sausage cooks, finely mince the fresh rosemary leaves.
In a small bowl, whisk together the large egg, egg whites, minced rosemary, sea salt, and black pepper until well combined.
Remove the cooked sausage from the skillet and set aside; add the ghee to the same skillet over medium-low heat.
Pour the egg mixture into the skillet and cook, stirring gently with a spatula to create soft, fluffy scrambles.
Lightly toast the whole grain bun until the edges are golden and crisp.
Assemble the sandwich by placing a handful of fresh arugula on the bottom bun, followed by the beef sausage and the rosemary eggs.
Close the sandwich with the top bun and serve immediately while hot.