Preheat your oven to 400°F (200°C).

Season the Tomahawk steak generously with salt and freshly ground black pepper. Rub the crushed pink peppercorns all over the steak, ensuring it is evenly coated.

In a large oven-safe skillet, heat the olive oil over medium-high heat. Once hot, add the Tomahawk steak and sear for about 4-5 minutes on each side until a golden-brown crust forms.

Remove the steak from the skillet and set aside. In the same skillet, add the sliced leeks and sauté for about 5-7 minutes, until softened and slightly caramelized.

Return the Tomahawk steak to the skillet, placing it over the leeks. Transfer the skillet to the preheated oven and roast for 25-30 minutes, or until the internal temperature reaches your desired doneness (135°F for medium-rare, 145°F for medium).

While the steak is roasting, prepare the brown butter sage reduction. In a small saucepan, melt the butter over medium heat. Add the sage leaves and garlic, cooking until the butter turns golden brown and the garlic is fragrant (about 3-4 minutes). Be careful not to burn the garlic.

Remove the saucepan from heat and stir in the lemon zest and juice. Set aside.

Once the Tomahawk steak is done roasting, remove it from the oven and let it rest for 10-15 minutes before slicing.

To serve, slice the Tomahawk steak and arrange it on a platter over the roasted leeks. Drizzle the brown butter sage reduction over the top and garnish with additional fresh sage if desired.