Preheat oven to 375°F (190°C).

Let steaks sit at room temperature.

Heat a cast-iron skillet over medium heat.

Season steaks aggressively with salt and pepper.

Increase skillet heat to high and add oil.

Sear steaks for 2 minutes per side.

Smear butter on top of steaks after flipping.

Transfer skillet to the oven and roast for 6-10 minutes, basting with pan juices.

Check for doneness using a thermometer (115-130°F for desired doneness).

Transfer steaks to a cutting board to rest for 5-10 minutes.

Pour pan drippings over steaks and serve.

For the sauce, tear orange and grapefruit zests.

Combine zests, raisins, gin/water, and red pepper flakes and soak for 4-6 hours.

Soak tamarind pulp in warm water, then strain to extract juice.

Sauté onions in oil until translucent.

Add garlic, cloves, allspice, and cinnamon and sauté until fragrant.

Stir in tomato paste and sugar and cook until the pan bottom darkens.

Add soaked raisins and zest and simmer briefly.

Add grapefruit juice, orange juice, vinegar, and tamarind juice and simmer until reduced by one third.

Strain the sauce and cool to room temperature.

Refrigerate for up to 3 weeks.