Preheat oven to 425°F and place a large rimmed baking sheet in the oven to preheat.
In a large bowl, toss the carrots with 1 tbsp olive oil, crushed coriander seeds, and 1/4 tsp each salt and pepper.
Carefully arrange the carrots on the hot baking sheet and roast until golden brown and tender, 20 to 28 minutes depending on carrot thickness. Immediately drizzle with honey and toss to coat.
While the carrots roast, heat 1 tbsp olive oil in a large cast-iron skillet over medium-high heat. Season the hanger steak with 1/2 tsp salt and 1/2 tsp pepper.
Sear the steak on all sides for 2 to 4 minutes per side or until desired doneness is reached. Transfer to a cutting board and let rest for at least 5 minutes before slicing.
In a small bowl, mash the softened butter with harissa and a pinch each of salt and pepper.
Serve sliced steak topped with harissa butter and a generous portion of honey-roasted carrots.