Cook the onion and garlic with 1 tsp oil in a frying pan over a medium heat, stirring occasionally, until softened. Remove half the mixture from the pan and put in a large bowl to cool. When cool, add the mince and egg, season well and mix together. Remove the rest of the onions and garlic from the pan and put in another bowl.

Heat the remaining 1/2 tsp oil in a frying pan over a medium-low heat and fry the pancetta for a couple of minutes until the fat starts to melt. Tip in the reserved onions and garlic and cook for 8-10 mins until golden. Set aside.

Take a third of the potatoes, chop each into four and put in a large pan of cold salted water. Bring to the boil and simmer for 15 mins until cooked. Drain in a colander, then leave to steam-dry for 5 mins. Crush the potatoes as smooth as you can with a masher or use a potato ricer.

Finely grate the remaining raw potatoes using a food processor. Squeeze the grated potatoes through a muslin or tea towel over a bowl to squeeze out as much liquid as possible. Set the bowl of liquid aside and after 5-10 mins it will separate with the potato starch at the bottom of the bowl. Carefully drain off the water, then scrape the starch back into the bowl of raw potatoes. Stir in the citric acid or lemon juice – this will prevent the cepelinai becoming very dark. Add the cooked mashed potato to the raw, add the 2 tbsp potato starch or cornflour, season well and mix to combine.

Bring a large pan of salted water to the boil. Season the potato mixture and shape into palm-sized 2cm thin cakes. Add the mince mixture and roll between your palms into large egg shapes, packing the potato around the mince tightly – it helps to wet your hands for this. Add them to the simmering water one at a time and cook for 20-25 mins – when they float to the surface they are done.

To serve, warm up the pancetta mix. Put two cepelinai on each plate, add a dollop of soured cream and top with the pancetta mix and dill.