New York Strip

I'm very good at cooking filet mignon but I haven't mastered the New York Strip. The last two times I have tried searing it with just salt and pepper but it isn't working out. The outside is char-crusted, which is good, but the middle is nearly rare and mushy and the fat doesn't render. While cooking this one today I was certain it would be overcooked after resting in a foil tent, but instead it was chewy, yet browned on the outside to the verge of burning. I'm not doing something right. I think I need to use the oven to finish it, not sure. I have a couple more in the freezer and I will definitely take a different path next time. I'm pretty sure it will involve butter, just like the filet, but also different application of heat.