Cast-Iron Porterhouse with Garlic Butter

Ingredients

• 1 porterhouse steak, about 900 g (2 lb) and 4 cm (1½ in) thick
• 2 tsp coarse salt
• 1 tsp black pepper
• 1 tbsp high-heat oil, such as avocado or grapeseed
• 45 g (3 tbsp) butter
• 4 cloves garlic, smashed
• 3 sprigs thyme
• 1 sprig rosemary
• Flaky salt, to finish

Steps

1. An hour before cooking, pat the steak dry and season all over with the coarse salt and pepper. Leave it uncovered at room temperature.
2. Heat the oven to 200°C (400°F). Set a large cast-iron skillet over high heat for 5 minutes, until very hot, then add the oil.
3. Sear the steak for 3 minutes per side, without moving it, until a dark brown crust forms. Hold it on its edge for 30 seconds to colour the fat strip.
4. Lower the heat to medium. Add the butter, garlic, thyme and rosemary. When the butter foams, tilt the pan and spoon it over the steak for 1 minute.
5. Slide the skillet into the oven for 4–6 minutes, until the centre reads 52°C (125°F) for rare or 54–57°C (130–135°F) for medium-rare. The handle will be very hot.
6. Move the steak to a board and rest for 8 minutes, spooning the pan butter over.
7. Cut the strip and tenderloin sides away from the bone, slice them against the grain, and pour the garlic butter from the pan over. Finish with flaky salt.

Notes

• Smoke: this is a smoky job; turn on the extractor fan and open a window.
• Two sides, two textures: the tenderloin is the smaller, leaner side and cooks faster. While searing, keep the tenderloin side toward the cooler edge of the pan.
• Thicker steak? For a 5 cm (2 in) cut, use a 150°C (300°F) oven for 10–12 minutes after searing, so the centre catches up gently.
• Chef's touch: squeeze a little lemon into the garlic butter off the heat; the acid cuts through the richness.
• Pair with: creamed spinach or a crisp wedge salad, steakhouse style.