Creamy Sliced Steak and Potatoes

1 ½ teaspoons vegetable oil

½ slice onion, diced

14 ounces beef top sirloin, thinly sliced

1 (15 ounce) can whole new potatoes, drained

1 (10.75 ounce) can condensed cream of mushroom soup

¼ cup milk

salt and pepper to taste

Heat the vegetable oil in a skillet over medium heat. Stir in the onions, and cook until they begin to soften, about 3 minutes. Increase the heat to medium-high, and add the sliced sirloin. Cook and stir until the meat is no longer pink, and beginning to brown around the edges, about 7 minutes. Add the potatoes, cream of mushroom soup, and milk. Bring to a simmer, then reduce the heat to medium-low, and simmer 10 minutes. Season to taste with salt and pepper before serving.