Dice the russet potato into small, uniform 1/2-inch cubes to ensure even and rapid cooking.
Heat the olive oil in a large cast-iron skillet over medium-high heat until shimmering.
Add the potato cubes to the skillet in a single layer and cook for 8-10 minutes, stirring occasionally, until they are golden-brown and tender.
Slice the chicken sausage into rounds and add them to the skillet along with the diced onion and red bell pepper.
Sauté the mixture for another 5 minutes until the sausage is browned and the vegetables are softened.
In a small bowl, whisk together the whole egg, egg whites, sea salt, black pepper, and smoked paprika.
Reduce the heat to medium and pour the egg mixture over the sausage and potatoes, stirring gently to incorporate.
Cook for 2-3 minutes until the eggs are just set but still moist, then garnish with fresh parsley and serve immediately.