Preheat your oven to 400°F (200°C). Gather all ingredients and ensure your bison ribeye steaks are at room temperature.

In a bowl, combine the chopped roasted chestnuts, fresh rosemary, garlic powder, salt, and pepper. Mix well to combine and set aside.

Heat olive oil in a large cast-iron skillet over medium-high heat. Season the bison ribeye steaks generously with salt and pepper. Once the oil is hot, add the steaks to the skillet and sear for about 3-4 minutes on each side until browned.

Remove the skillet from heat and evenly press the chestnut and rosemary mixture onto the top of each steak, ensuring the crust adheres well.

Transfer the skillet to the preheated oven and roast for 8-10 minutes for medium-rare, or until the desired doneness is achieved. Use a meat thermometer for accuracy (130°F for medium-rare).

In a mixing bowl, combine the softened butter, shredded smoked gouda, chopped chives, and lemon juice. Use a hand mixer or whisk to whip until well combined and creamy.

Once cooked, remove the steaks from the oven and let them rest for 5-7 minutes to retain their juices.

Slice the bison ribeye steaks against the grain, and serve topped with a dollop of whipped smoked gouda and chive butter.