Combine the frozen hash browns cheese and onion in a large bowlCombine the milk beef stock half of the melted butter garlic powder salt and black pepper in another bowl and mix until well blended
Pour over hash browns and mix well
Heat the remaining butter in a large ovenproof skillet over high heatWhen the skillet is hot spoon in the hash brown mixture
Cook the hash browns stirring occasionally until hot and all of the cheese is melted about 7 minutesPut the skillet into the oven and bake for 45-60 minutes or until the surface for the hash browns are dark brown