Prepare the potatoes. Wash and scrub the potatoes. Using a box grater or a food processor with a grating disc, grate the potatoes. They should look like fine, delicate shreds. Immediately place the grated potato into a large bowl of cold water. Swish them around to release the starch; the water will turn milky white. This step is crucial for achieving a crisp result.

Soak and rinse. Let the potatoes soak in the cold water for at least 10 minutes. Then, drain them in a colander and rinse under cold running water until the water runs clear. The smell of clean, fresh potato is a good sign. Squeeze out as much water as you can from the shreds with your hands.

Dry and squeeze. This is the most important step. Tip the grated potato onto a clean tea towel. Gather the corners of the towel and twist it tightly over the sink, wringing out every last drop of water. You will be amazed at how much liquid comes out. The dryer the shreds, the crispier the hash browns. You should hear a faint squeak when you squeeze them.

Combine the batter. In a large mixing bowl, combine the squeezed-dry potato shreds, the finely grated onion, beaten egg, flour, salt, pepper, and garlic powder (if using). Use a fork to mix everything together until it is evenly combined. The mixture will look a little coarse and lumpy, which is exactly what we want. The scent of onion and pepper will be subtle and inviting.

Rest the mixture. Cover the bowl with a plate or cling film and let it rest at room temperature for 10 minutes. This allows the flour to hydrate and the flavours to meld. You'll notice the mixture becomes slightly more cohesive. This rest is a secret to hash browns that hold together perfectly in the pan.

Heat the pan. Place your large frying pan or skillet over a medium-high heat. Add 1 tablespoon of butter and 1 tablespoon of oil. Wait until the butter has melted, foamed, and the foam has subsided. The butter should be sizzling gently, not smoking. The aroma of browning butter is the signal that the pan is ready.

Shape and fry. Using about ¼ cup of the potato mixture per hash brown, shape it into a rough patty about 1cm thick. Gently place it into the hot butter and oil. You should hear a satisfying, immediate sizzle. Do not overcrowd the pan; cook in batches of 3-4, leaving space between each patty. The sound should be a steady, happy hiss.

Cook until golden and crisp. Let the hash browns cook undisturbed for 4-6 minutes. You will see the edges turning a deep, golden brown. The centre of the patty will start to look slightly dry. When the bottom is deeply browned and crisp, carefully flip each one with a spatula. Cook for another 4-5 minutes, until the second side is equally golden and the hash brown is cooked through. When you press the centre with your spatula, it should feel firm and offer a gentle resistance. The kitchen will smell gloriously of toasted potato and butter.

Drain and serve. Transfer the cooked hash browns to a wire rack set over a baking sheet. This keeps them crisp, as opposed to placing them on paper towels which can create steam. Sprinkle immediately with flaky sea salt while they are still hot. Serve at once, while the outside is shatteringly crisp and the inside is soft and steamy.