Peel and slice raw potatoes. Add oil to a skillet and add and brown potatoes until almost done about 10-15 minutes.
While potatoes are cooking put cold cooked beef in the blender in chunks until shredded nicely. Add to potatoes and cook until nice and crispy. You may use butter instead of oil and use redskin potatoes. Also I have precooked the potatoes to cut down on frying time.
Salt and pepper to your taste and we like to top it with ketchup when done on our plates not in the skillet. Adjust the amount of potatoes to the amount of beef you have left over.