Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Dice the Yukon gold potatoes into small cubes and break the cauliflower into bite-sized florets.
In a mixing bowl, toss the potatoes and cauliflower with half of the olive oil, half of the sea salt, and half of the black pepper.
Spread the vegetables in a single layer on the baking sheet and roast for 20-25 minutes until the potatoes are tender and golden-brown.
While the vegetables roast, pat the steak dry with a paper towel and season both sides with the remaining salt and pepper.
Heat the remaining olive oil in a cast-iron skillet over medium-high heat until shimmering.
Place the steak in the skillet and sear for 3-4 minutes per side for a medium-rare finish.
During the last minute of searing, add the minced garlic, rosemary, and thyme to the pan, spooning the infused oil over the steak.
Remove the steak from the heat and let it rest for 5 minutes before slicing against the grain.
Plate the sliced steak alongside the roasted potatoes and cauliflower, drizzling any remaining pan juices over the meat.