Preheat your oven to 400°F (200°C).
Peel the sweet potatoes and cut them into uniform 1-inch cubes.
Place the sweet potato cubes on a large baking sheet and toss with 1 tablespoon of olive oil, 0.5 teaspoon of sea salt, and 0.25 teaspoon of black pepper.
Roast the sweet potatoes for 25-30 minutes, flipping halfway through, until they are golden brown and tender.
While the potatoes roast, pat the ribeye steaks dry with paper towels and season both sides with the remaining salt and pepper.
Heat a large cast-iron skillet over medium-high heat and add the remaining tablespoon of olive oil.
Place the steaks in the hot skillet and sear for 4-5 minutes per side for medium-rare, or until your desired level of doneness is reached.
During the last 2 minutes of searing, add the smashed garlic cloves and fresh rosemary sprigs to the pan, spooning the infused oil over the steaks.
Remove the steaks from the skillet and let them rest on a cutting board for at least 5-10 minutes to lock in the juices.
Slice the steak against the grain and serve alongside a generous portion of the roasted sweet potatoes.