Season onions and mushrooms with salt and pepper. Add butter and sautee until onions are translucent.
Combine all prepared ingredients-except hashbrowns, cornflakes, and 4oz butter-into a large bowl and mix
Once combined, incorpoate frozen hashbrowns into the same bowl and mix until homogenous.
Turn mixture into a greased pan (9x13 in)
Roughly crush (don't powder) the Corn Flakes
Slowly pour and stir melted butter to coat topping evenly
Spread topping evenly over potato mixture.
Bake at 350 for 30 min. May take longer
Watch browning on top and bubbling underneath.
