Heat oven to 350°F; line a 9-by-13-inch pan with parchment. Split connected rolls horizontally; put bottoms in pan.

Spread mustard thinly over bottoms. Layer half the cheddar, folded beef, dry pepper strips, and remaining cheddar.

Replace tops; brush with butter mixed with garlic powder. Cover loosely with foil.

Bake 15 minutes. Uncover; bake 8 to 10 minutes until cheese melts and center reaches 165°F.

Rest 5 minutes; cut into 12 sliders with a serrated knife.