Pound sandwich steaks to even thickness using a meat mallet.
Mix bread crumbs, egg, garlic powder, salt, and pepper together in a bowl. Spread over steaks in an even layer. Roll steaks into tight spirals and secure with toothpicks.
Heat oil in a large skillet over medium heat. Cook steak rolls until browned, 1 to 2 minutes per side. Sprinkle onion soup mix into the skillet. Fill the empty package with water and pour into the skillet twice. Cover skillet; bring to a boil. Reduce heat to low and simmer, covered, until flavors combine, 45 to 60 minutes.