Preheat the oven to 180°C/Fan 160°C/Gas 4. Cook the potatoes whole in a pan of boiling water for 10 minutes. Drain and leave to cool a little.
Grate the potatoes into a mixing bowl and add the remaining potato cake ingredients, season with salt and pepper.
Line two baking trays with parchment and drizzle each with a little oil. Make 12 small balls of the potato cake mixture, place in the oven and cook for 20-30 minutes. Half way through cooking time, squash each mound down into a flat disk and flip.
Mix together the dill yoghurt ingredients and season to taste with salt and pepper and a little extra lemon juice if needed. Freeze for a simple snack throughout the week, or serve with a poached egg or some flaked smoked mackerel for a delicious weekend brunch.