Bring the ribeye to room temperature (20–30 minutes) and pat it very dry with paper towels. This evens out cooking so the steak cooks more uniformly and a dry surface is essential to getting a Maillard crust.

Season the steak generously on both sides with kosher salt and a generous crack of black pepper just before cooking. Salting early draws moisture out and then back in; for a short rest at room temp, salt now to flavor the interior without making the surface wet.

Prep the vegetables while the steak comes to temp: trim the green beans and roughly chop the cauliflower into uniform florets (2 cups). Evenly sized pieces steam faster and mash more smoothly.

Steam or simmer the cauliflower in salted water until very tender, 8–10 minutes. Cook until a fork slides through easily — overcooking will make it soggy, undercooking gives grainy mash. Drain thoroughly and let sit in the colander while you cook the steak to remove excess water (drier cauliflower = fluffier mash).

Heat a heavy cast‑iron skillet or grill pan over high heat until just smoking. High heat is what creates a crisp, savory crust; a cold pan will make the steak stew instead of sear.

Add 1 tablespoon olive oil to the hot pan and place the ribeye in the pan. Sear without moving for 2½–3 minutes to develop a deep brown crust. Flip and sear the other side another 2½–3 minutes for medium‑rare on a 10‑oz, 1–1¼" thick ribeye; adjust by a minute per side for thickness and desired doneness.

Use an instant‑read thermometer for accuracy: target 120–125°F (49–52°C) for rare, 125–130°F (52–54°C) for medium‑rare, 135°F (57°C) for medium. Remove the steak at 5–8°F (3–4°C) below final temp — carryover cooking will raise it as it rests.

Transfer the steak to a cutting board and tent loosely with foil. Rest 6–8 minutes. Resting lets the muscle fibers relax and reabsorb juices, keeping the steak tender and juicy when you slice.

While the steak rests, make the garlic‑parsley cauliflower mash: heat the remaining 1 tablespoon olive oil in a small skillet over medium heat and gently sauté the minced garlic just until fragrant, about 30‑45 seconds — you want golden aromatic garlic, not bitter burnt garlic. Remove from heat.

Transfer the drained cauliflower to a food processor or use an immersion blender. Add the sautéed garlic and oil, chopped parsley, and a big pinch of salt and pepper. Pulse/blend to a smooth but slightly textured puree. Taste and adjust seasoning. If it feels too thick or dry, add 1–2 tablespoons warm water (or a splash of broth) — avoid cold liquids, which can cool and tighten the puree.

Blanch the green beans: bring a small pot of salted water to a boil and add the trimmed beans for 2 minutes, then immediately transfer to an ice bath to preserve bright color and snap. This quick blanch reduces the final sauté time and prevents overcooking.

Heat the still‑hot skillet (used for steak) over medium and add the blanched green beans to pick up any fond left from the steak for extra flavor. If your pan is dry, add a quick drizzle of olive oil. Toss for 2–3 minutes until bright, tender‑crisp; finish with a pinch of salt and a crack of pepper. Using the steak pan lets the beans pick up meaty caramelized notes from the fond.

Slice the rested ribeye against the grain into 1/4–1/2" slices to maximize tenderness. Plate a generous scoop of cauliflower mash, fan the steak slices on top or alongside, and arrange the sautéed green beans as a vibrant accent.

Finish each plate with a few turns of freshly ground black pepper and a scattering of the remaining chopped parsley for color and a fresh herbal lift. Serve immediately.