Mustard Sauce

1. Combine the mustard, honey, and caper liquid in a small mixing bowl. Whisk until smooth. Drizzle in the olive oil, whisking until emulsified.
2. Stir in the capers, cayenne pepper, and scallions. Season with a pinch of salt to taste and set aside. 

Seared Strip Steak with Crispy Potatoes 

1. Preheat the oven to 400°F. Allow the steak to come to room temperature. 
2. Place the potatoes and radishes onto a half sheet pan. Drizzle generously with olive oil and toss to coat. Spread the vegetables out into an even layer, potatoes halved-side down. Season with a good pinch of salt and black pepper. Roast for 15 minutes. 
3. Evenly distribute the sliced asparagus and shallot onto the pan. Drizzle with a little more olive oil. Continue to roast for about 15-20 more minutes, or until the potatoes are golden and tender.
4. Meanwhile, pat the steak dry and season well with salt & freshly cracked black pepper. Heat a stainless steel pan (or cast-iron skillet) over medium-high heat. Once the pan is hot, add enough oil to just cover the bottom. Once the oil is hot, carefully place the steak into the pan. 
5. Sear on one side for 3-4 minutes until golden and crisp. Flip the steak over and sear for another 3-4 minutes. Turn the heat to low and finish cooking the steak for about 6-8 more minutes, or until your desired doneness, flipping halfway through. Transfer the steak to a cutting board and cover loosely with foil. Let rest for 5 minutes. 
6. Thinly slice the steak and serve alongside the roasted potato mixture. Drizzle the mustard sauce over top. Garnish with the chives and a few cracks of black pepper.