Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Peel and cube the sweet potato into half-inch pieces, then trim the tough ends off the broccolini.
Toss the sweet potatoes and broccolini on the baking sheet with olive oil and half of the salt, pepper, and garlic powder.
Roast the vegetables for 20 to 25 minutes, or until the potatoes are fork-tender and the broccolini has crispy, charred edges.
While the vegetables roast, pat the steak dry with a paper towel and season both sides with the remaining salt, pepper, and garlic powder.
Heat a cast-iron skillet over medium-high heat and add the ghee, allowing it to melt and shimmer.
Place the steak in the hot skillet and sear for 3 to 4 minutes per side for medium-rare, or until it reaches your preferred level of doneness.
Remove the steak from the pan and let it rest on a cutting board for 5 minutes before slicing against the grain to maintain juiciness.
Plate the sliced steak alongside the roasted sweet potatoes and broccolini for a complete, clean-eating meal.