Preheat the oven to 400°F (200°C).

In a small skillet over medium heat, toast the mustard seeds until they begin to pop, about 2-3 minutes. Remove from heat and set aside.

Heat a grill pan or cast-iron skillet over high heat. Add the green onions and char them for about 2 minutes on each side until they are nicely grilled. Remove from the pan and chop them into small pieces.

Season the New York strip steaks generously with salt and freshly cracked black pepper on both sides.

In the same skillet, add olive oil and heat over medium-high heat. Once hot, add the steaks and sear for 4-5 minutes on each side for medium-rare.

While the steaks are cooking, melt the butter in another small skillet over medium heat. Add the chopped shallots and sauté until they are translucent and lightly browned, about 3-4 minutes. Stir in thyme, lemon zest, and lemon juice, then remove from heat.

Once the steaks are cooked to your liking, remove them from the heat and let them rest for 5 minutes.

To assemble, spread the charred green onions over the top of the steaks, then sprinkle the toasted mustard seeds evenly on top.

Drizzle the browned shallot butter over the steaks just before serving.

Serve immediately, garnished with additional thyme if desired.