Start by grating the peeled parsnips using a box grater or a food processor. Place the grated parsnips in a clean kitchen towel and squeeze out any excess moisture.

In a large bowl, combine the grated parsnips, chopped onion, flour, salt, and black pepper. Mix well until all the ingredients are evenly combined.

Heat the vegetable oil in a large non-stick skillet over medium heat.

Take a handful of the parsnip mixture and shape it into a small patty. Gently place it in the hot skillet and flatten it slightly with a spatula. Repeat this process with the remaining parsnip mixture, making sure not to overcrowd the pan.

Cook the rösti for about 2-3 minutes on each side, or until golden brown and crispy. Flip them carefully using a spatula.

Once cooked, transfer the rösti to a paper towel-lined plate to absorb any excess oil.