Preheat your oven to 400°F (200°C).

In a small bowl, combine the minced garlic, chopped sage, and olive oil. Season with salt and pepper.

Rub the garlic and sage mixture all over the New York strip steaks. Let them marinate at room temperature for 30 minutes.

While the steaks are marinating, heat a large skillet over medium heat. Add the sliced onions and cook, stirring occasionally, until they become caramelized and golden brown, about 15-20 minutes. If they begin to stick, add a splash of water to deglaze the pan.

Once the onions are caramelized, stir in the black garlic and balsamic vinegar. Cook for an additional 2 minutes. Remove from heat and set aside.

Heat an oven-safe skillet over high heat. Once hot, add the steaks and sear for about 3-4 minutes on each side until a nice crust forms.

Transfer the skillet to the preheated oven to finish cooking the steaks to your desired doneness (about 5-7 minutes for medium-rare).

While the steaks are in the oven, prepare the butter. In a small saucepan, melt the unsalted butter over medium-low heat. Stir in the caramelized onion and black garlic mixture. Keep warm.

Once the steaks are done, remove them from the oven and let them rest for 5 minutes.

Serve the steaks topped with the caramelized onion and black garlic butter. Garnish with fresh parsley.