Peel the 500 g of Agria potatoes.

Coarsely grate the peeled potatoes into a mixing bowl.

Cover the grated potatoes with cold or iced water. Soak for 2 min to remove surface starch.

Drain the potatoes thoroughly in a colander.

Wrap the drained potatoes in a clean kitchen towel. Squeeze firmly to remove as much moisture as possible.

Season the dry grated potatoes with 2 g salt and 1 g black pepper. Toss until evenly seasoned.

Heat 15 ml olive oil and 14 g clarified butter in a frying pan over medium heat.

Add the seasoned grated potatoes to the hot pan. Press them into one compact, even round disk.

Cook the rösti undisturbed for 8 to 10 min over medium heat. Cook until the underside is deeply golden and crisp.

Place a plate over the frying pan and carefully invert the rösti onto it. Slide the rösti back into the pan with the uncooked side down.

Cook the second side for 8 to 10 min over medium heat. Cook until golden, crisp, and tender in the center.

Add 55 g feta cheese and 15 g harissa to the edge of the pan. Fry the feta and harissa for 2 to 3 min until hot and lightly browned.

Crack 1 egg into the pan beside or over the rösti. Fry for 2 to 3 min until the white is set and the yolk remains runny.

Transfer the crispy rösti to a plate. Top with the fried egg, feta, and harissa, then serve immediately.