Preheat your oven to 400°F and line a small baking sheet with parchment paper.
Halve the baby potatoes and toss them with 0.5 tsp of olive oil and a pinch of salt and pepper.
Roast the potatoes for 20 minutes, adding the trimmed asparagus spears to the pan for the final 8 minutes of cooking.
While vegetables roast, pat the steak completely dry with paper towels and season both sides with the remaining salt and pepper.
Heat the remaining 0.5 tsp of olive oil in a cast-iron skillet over medium-high heat until it begins to shimmer.
Place the steak in the hot skillet and sear for 3 to 4 minutes per side to achieve a medium-rare finish.
Reduce the heat to low and add the ghee, smashed garlic clove, and thyme sprig to the side of the pan.
Tilt the skillet slightly so the melting ghee pools with the garlic and thyme, then spoon the flavored fat over the steak repeatedly for 1 minute.
Remove the steak from the pan and let it rest on a cutting board for 5 minutes before slicing against the grain.
Serve the sliced steak alongside the roasted potatoes and asparagus, drizzling any remaining pan juices over the top.