Heat a skillet over medium heat. Add the meat and place a lid over the top, and then turn the heat to medium low.
1 lb thinly sliced, deli roast beef
Meanwhile, stir together the Arby's sauce ingredients and spread on the buns.
4 onion buns, 1/2 cup ketchup, 2 tsp water, 1/4 tsp garlic powder, 1/4 tsp onion powder, pinch of salt
In a pot on the stove on medium-low heat, add cheese, milk, garlic powder, and pepper and stir until completely melted and evenly combined.
5 slices American cheese, 3 tbsp milk, 1/4 tsp garlic powder, ground black pepper, to taste
Place the meat on the buns, add the cheese sauce, and a little more Arby's sauce (if desired). Top the sandwiches off with their other half.
Serve immediately, with curly fries, for an authentic in-home Arby's experience.