01 -
Heat oven to 400°F. Butter 9x13 dish.
02 -
Cook onions in butter, add garlic. Stir in flour until tan. Whisk in stock until thick, add cheese.
03 -
Mix sauce with frozen hash browns, spread in dish.
04 -
Cook 45 minutes, then broil 5 minutes for crispy top.
05 -
Fry serrano slices in oil until brown. Drain and salt.