In a spacious mixing bowl, combine the mashed potatoes, cooked ground beef, shredded cheddar cheese, finely chopped green onions, beaten egg, all-purpose flour, garlic powder, onion powder, salt, and pepper. Ensure thorough mixing until all ingredients are well incorporated.
Heat oil in a large skillet over medium heat, ensuring it’s adequately hot for frying.
Form the potato mixture into palm-sized cakes, approximately 1/2 inch thick, shaping them with care.
Carefully fry the cakes in the hot oil until they achieve a beautiful golden brown color and crispiness, typically requiring about 3-4 minutes per side.
Once fried to perfection, transfer the potato cakes to a plate lined with paper towels to drain excess oil.
Serve these tantalizing potato cakes hot, accompanied by a generous dollop of sour cream on top, adding a delightful creamy contrast to the savory flavors.