Most hash brown potatoes found in restaurants or private homes are loosely mixed combinations of potato cubes or grated/shredded potatoes and chopped onion with salt and pepper, fried in rendered bacon fat or soybean or equivalent vegetable oils. The type of hash brown patties found at fast food restaurants and freezer sections of supermarkets are a definite improvement over most of the home made and typical restaurant style hash brown potatoes. Why? The primary reason is that the water contained in the potato cubes or grated/shredded potatoes is fried from the surface of the potato but the interior is typically mushy soft after cooking. In other words, water is the problem.
Removing enough water from cubed potato pieces before frying is impractical for the home cook, so the best idea is to grate or shred the potatoes, rinse the pieces in water to remove excess starch, and then drain the pieces well in a colander and then press the potato pieces in a thin layer between dish towels, and then paper towels, to remove most of the moisture. You can be more sophisticated and follow the Food Nirvana recipe for preparing potatoes for French Fries by parboiling the potato pieces briefly, one to two minutes, in water that contains a small amount of white distilled vinegar and a bit of kosher salt. In that case the parboiled pieces are drained in a colander and then distributed in a very thin layer on a dish towel and allowed to air dry at room temperature for half an hour prior to frying. The pieces should look and feel fairly dry on all surfaces. They will not oxidize and turn brown due to the vinegar used in parboiling.
1 pound of Yukon Gold or Russet potatoes, washed, peeled and grated/shredded
1 shallot, peeled (or a small onion) and then grated (or finely diced)
1/2 cup of shredded Cheddar Cheese
1/3 cup of all-purpose flour
2 tablespoons of chopped fresh parsley (optional)
1 extra large egg, lightly whisked
1/2 tsp. of Kosher salt and 1/2 tsp. of freshly ground black pepper
Peanut oil, or rendered bacon fat, for frying
Grate/shred the potatoes and finely dice or grate the shallot/onion using your food processor or a manual grater and/or a paring knife. Add the pieces to a colander, rinse well with cold water, and squeeze dry using a clean dish towel, making sure to get rid of all of the surface moisture.
Place the potato and shallot/onion pieces into a two quart bowl along with the cheese, flour, parsley, whisked egg and one half teaspoon of Kosher salt and one half teaspoon of ground pepper. Mix well using your hands or a large wooden spoon.
Heat about 1/4 cup of peanut oil (or a 1/8 inch thick layer of melted bacon fat) in a large cast-iron (or non-stick heavy bottom) skillet until hot (roughly 360 degrees F, which you can check easily with an instant read thermometer by tipping the skillet slightly and pooling the oil/melted fat on one side of the skillet).
Scoop 1/4 to 1/3 cup of the potato mixture into the skillet and flatten it with a spatula until the patty is 1/2 inch thick in the middle. --> TIP: If the under side of the spatula is slippery with a bit of the cooking oil/fat then the patty surface will not stick to the spatula during flattening. Repeat for the remaining patties leaving an inch of space on all sides to allow later easy use of the spatula to flip the patties.
Fry the patties on medium to medium high heat until they are golden and crisp, 2 to 3 minutes on the first side, and then flip and fry them for another 2 minutes on the second side. Remove the fried hash brown patties to a paper towel lined baking sheet to absorb excess cooking oil/fat. Repeat in batches.
Keep the hash brown potato patties warm and fairly crisp before serving by placing them in a single layer on a wire rack set over a baking sheet, and put the baking sheet into a 200 degree F warming oven. The patties are best in terms of crispness when served immediately after frying, so you may want to prepare other meal items before frying the hash brown patties.