Preheat your oven to 400 degrees.
Allow the flank steak to reach room temperature on your counter for 20 minutes.
Meanwhile, peel then quarter your sweet potatoes and cut them into ½-inch slices.
In a large frying pan, heat 2 tablespoons of oil over medium-high heat. Sauté the potatoes for 4 minutes, flipping halfway.
Pour in a ¼ cup of white wine or water to deglaze the pan. Turn down the heat to medium-low, add the onions, garlic, salt, pepper, and cook for another 3–4 minutes.
In a small bowl, combine the adobo, granulated garlic, onion powder, paprika, oregano, salt, and pepper and rub onto the flank steak.
Move the sweet potatoes to the sides of the pan (scraping up any bits that may still be left over from the sauté). Turn the heat back to medium-high and pour 2 tablespoons of oil into the center of the pan.
Sear the steak on both sides for 3 minutes. Then place in the oven for another 2–3 minutes or until your desired doneness.
Let rest for five minutes, garnish with parsley, and serve hot.