American Wagyu Filet Mignon

The filet mignon is the outlier in the wagyu conversation. Most wagyu obsessives chase ribeyes and striploins — cuts with heavy fat caps where marbling has room to show off. The filet, by nature, is the leanest muscle on the animal (the psoas major, which never really works), so getting it to a Marble Score 9+ is a serious feat of genetics and feeding. Masami Ranch has cracked that code.

Masami Ranch operates with a philosophy borrowed directly from Japanese producers: slow growth, low stress, and a silage and grain program calibrated to develop intramuscular fat gradually rather than forcing it. The Northern California climate — mild, dry, consistent — keeps the cattle calm and comfortable, which matters more than most people realize. Stressed cattle produce tougher, less evenly marbled meat. Masami's environment is basically the anti-feedlot.

MS 9+ — among the highest marble scores achievable in American Wagyu, rivaling the lower tiers of Japanese A5

Psoas major muscle — the least-worked muscle on the steer, making it structurally the most tender cut available

Japanese husbandry standards applied in California — the best of both production philosophies

We handpick Masami's program specifically because they don't cut corners on finishing time — these animals are on feed longer than conventional wagyu programs

The Most Important Rule: Less Is More

A Marble Score 9+ filet from Masami renders fat rapidly. High heat for too long will cook out the very marbling you paid for. Your goal is a hard sear, short cook, long rest.

Recommended Method: Cast Iron Reverse Sear (Best Results)

Pull the steak from the fridge 30–45 minutes before cooking. Tempering is more critical here than with conventional beef because the fat begins softening even at room temperature — a cold center means your sear time doubles, and that's where you lose the marbling.

Season simply: kosher salt and cracked black pepper only. This cut has enough going on internally — don't compete with it.

Preheat your oven to 250°F. Place the steak on a wire rack over a sheet pan and bring it to an internal temp of 110°F (roughly 20–30 minutes). This is your reverse sear phase.

While the steak finishes in the oven, get a cast iron skillet ripping hot — 2–3 minutes over high heat with a thin layer of high-smoke-point oil (avocado or refined beef tallow).

Sear 60–90 seconds per side, pressing gently for full contact. Sear the edges too — stand it up with tongs for 30 seconds per edge.

Optional: 1 tablespoon of unsalted butter, one crushed garlic clove, and a thyme sprig added in the last 30 seconds of searing. Baste continuously.

Target Temperatures

Medium-Rare: 130°F final internal temp — the sweet spot. Fat is fully fluid, texture is silky.

Medium: 135°F — acceptable, but you'll notice slightly less melt.

We strongly advise against cooking above medium on a 9+ marble score filet. You're paying for fat that renders at low temperatures — cooking to well-done is thermodynamically counterproductive.

Rest

Rest the steak loosely tented for 5–7 minutes. The filet retains heat efficiently due to its round, compact shape — don't skip this step or you'll lose juice on the cutting board instead of keeping it in the meat.

Alternate Method: Sous Vide + Sear

Set your water bath to 128°F for 45–60 minutes. Pat completely dry before searing — moisture is the enemy of crust formation. Sear for no more than 60 seconds per side on maximum heat. This method gives the most precise control over doneness and is ideal if you're serving guests.