How to Make It
Preheat the oven to 400°. In a small bowl, whisk the ají panca with the sake, vinegar, garlic, cumin and oregano and season with salt and pepper. Add 2 tablespoons of the grapeseed oil.
In another small bowl, whisk the ají amarillo with the soy sauce, lemon juice, yuzu juice and the remaining 2 tablespoons of oil.
Melt the butter in a medium skillet. Add the leeks, season with salt and pepper and cook over moderate heat, stirring frequently, until tender, about 8 minutes; keep warm.
Heat a cast-iron skillet. Brush the steaks with oil and season generously with salt and pepper. Cook over high heat, turning once, until browned, about 7 minutes. Transfer the skillet to the oven and roast the steaks for about 5 minutes for medium-rare meat.
Spoon the leeks onto plates and top with the steaks. Spoon both sauces on either side of the steaks and serve right away.
Peruvian ají panca and ají amarillo pastes are available at many Latin American food stores and by mail order from tienda.com.