Equipment
* optional
Ingredients
Tomahawk Steak
- 1200 g tomahawk steak, bone-in, at least 5cm thick
- 15 g kosher salt
- 5 g black pepper, freshly ground
- 15 ml neutral oil
- 50 g unsalted butter
- 3 garlic, crushed
- 3 fresh thyme, sprigs
Gruyere Potato Gratin
- 800 g yukon gold potatoes, peeled
- 300 ml heavy cream
- 100 ml whole milk
- 150 g gruyere cheese, freshly grated
- 50 g parmesan cheese, freshly grated
- 1 garlic, minced
- 1 g ground nutmeg
- 5 g kosher salt
Nutrition (per serving)
Method
Pat the raw tomahawk steak completely dry with paper towels. Season all sides generously with kosher salt. Place the steak on a wire rack set over a baking sheet and refrigerate uncovered for 12 to 24 hours. Wash your hands thoroughly and sanitize all surfaces after handling the raw meat to prevent cross-contamination.
The next day, begin the gratin. Slice the peeled potatoes uniformly to exactly 3 millimeters thick using a mandoline slicer. Do not rinse the sliced potatoes, as their surface starch is needed to thicken the cream.
In a medium saucepan, combine the heavy cream, whole milk, minced garlic, nutmeg, and 5g of salt. Bring to a gentle simmer over medium heat, stirring occasionally, then immediately remove from the heat.
Grease a gratin dish with butter. Arrange the potato slices in an overlapping shingled pattern. After every two layers of potatoes, sprinkle a handful of the mixed Gruyere and Parmesan cheeses. Pour the hot cream mixture evenly over the top, then finish with a generous final layer of cheese.
Preheat the oven to 200°C/400°F. Bake the potato gratin for 60 minutes until the top is deeply golden brown and the potatoes offer no resistance when pierced with a paring knife. Remove from the oven, cover tightly with heavy-duty foil to retain heat, and lower the oven temperature to 110°C/225°F.
Once the oven has cooled to 110°C/225°F, insert a meat thermometer probe into the dead center of the thickest part of the tomahawk steak, ensuring the tip does not touch the bone. Season with the black pepper. Roast on the wire rack until the internal temperature reaches exactly 46°C/115°F for a medium-rare finish. This will take between 60 to 90 minutes depending on exact thickness.
Heat a large cast-iron skillet over maximum high heat until practically smoking. Add the neutral oil. Carefully lay the steak into the pan and sear for exactly 60 seconds. Flip and sear the other side for 60 seconds. Use tongs to hold the steak upright and sear the fat cap edge for an additional 30 seconds to render the fat.
Reduce the heat to medium-low. Add the butter, crushed garlic, and fresh thyme to the skillet. Tilt the pan toward you and continuously baste the steak with the foaming, aromatic butter for 45 to 60 seconds to enrich the crust.
Transfer the tomahawk to a cutting board and let it rest for 10 minutes. The internal temperature will rise to a safe and perfect 54°C/130°F. Do not slice early, or the juices will flood the board.
Holding the exposed rib bone, slice cleanly downward along the contour of the bone to separate the meat. Slice the resulting massive ribeye across the grain into thick slabs. Uncover the warm gratin and serve alongside the carved steak.
Chef's Notes
- The tomahawk's bone insulates the meat directly touching it. Slicing the meat away from the bone before serving ensures guests aren't fighting with undercooked connective tissue.
- Rinsing sliced potatoes washes away amylose, the crucial starch needed to naturally thicken the cream in the gratin. Slice them directly onto your cutting board and leave them unwashed.
- If your oven runs hot, check the internal temperature of the steak after 45 minutes to prevent overcooking during the delicate reverse-sear phase.
- Residual carryover heat is immense on a cut this thick. Always pull the meat 5 to 7 degrees Celsius below your target final temperature.
Storage
Refrigerator: 3 days — Store leftover steak and gratin in separate airtight containers.
Reheating: Reheat gratin in a 175C/350F oven until bubbling. Gently reheat steak slices in a warm pan over low heat just until warmed through, being careful not to overcook.
