1. Combine the celeriac, potato, spring onions and salt in a large bowl and toss to combine. Heat one tablespoon of the butter in a 26cm frying pan over medium heat, swirling to coat the whole pan and edges.

2. Fill the pan with all the mixture but don't press it down (see tip). Cook for about 12 minutes until the bottom is crisp and browned, then firmly press down the mixture. Invert the rösti onto a large plate and return the pan to the heat.

3. Add the remaining butter and slide the rösti back into the pan, pushing it down into a firm cake and cooking for a further 10 minutes until well-browned on both sides and cooked through. Turn the rösti out, scatter with parsley, season with salt, and divide to serve.

Adam's tip Pressing down the rösti too early stops hot air and steam from cooking the upper layers of the potato cake, resulting in undercooked, starchy centres. Trust your pan and let the rösti cook down naturally

Suggestion: Serve with Adam's chicken cooked in cider for a hearty family meal.