Slice onions and cook in 2 tablespoons stick butter until soft and light brown. Remove and set aside.

Slice cube steak against the grain. Season with salt and pepper.

Heat 2 tablespoons butter over high heat (in same skillet) until melted and beginning to brown. Add meat in single layer. Cook one side until brown, then flip and cook until brown,.

Butter cut side of halved hoagie rolls, with remaining butter, and brown in skillet or on flat side of a grill pan.

To assemble, lay bottom half of roll on plate. Place meat mixture, followed by a spoonful of juice from the pan. Top with other half of roll. Cut in half before serving.