Preheat oven to 375°. Line a 15x10x1-in. pan with parchment. Remove the bottom of a 9-inch springform pan and place the round outer edge in the middle of the parchment., Place the potatoes, butter, salt and pepper in a large bowl; toss to coat. Layer a third of the potatoes evenly within the springform ring. Sprinkle with a third of the jalapenos and a third of the cheese. Repeat layers. Top with remaining potatoes and jalapenos., Bake for 35 minutes. Top with remaining cheese. Bake 15-20 minutes longer or until potatoes are tender. Let stand 5 minutes before removing ring. If desired, serve with salsa and sour cream.