"Cut the potatoes into 2.5cm (1 inch) chunks and cook them in boiling salted water until tender. Drain them, allow them to cool, then return them to the empty pan and add the flour. Lightly mash everything together but try to avoid stirring it up too much.Finely slice the chives and add them to the potatoes with a knob of butter, cheese (optional) and the baking powder, then mash a few more times. Season, then use your clean hands to bring the mixture together.Divide into 2 balls and dust with flour. Heat up your oven to a low temperature and place your plates in it to keep warm.Put a large frying pan on a medium-high heat and add a drizzle of olive oil. Add the potato balls and pat them down so they’re about 2cm (~ 1 inch) thick. Cook for around 10 minutes, turning them every few minutes until golden on both sides.Meanwhile, lightly beat the eggs so they are just broken and marbled. Season and put aside. When your potato scones are perfectly cooked, divide them between your plates and place back into the oven to keep warm, then take the pan off the heat and add a knob of butter. Once bubbling, pour in the eggs and put back on a low heat.Use a rubber spatula to gently sweep up the cooked layer of egg from the bottom of the pan every time it forms, so the uncooked egg can get down there and set. Remove the eggs from the heat once it looks three-quarters cooked – It will carry on cooking and by the time you mix it around one more time and serve on top of your potato cake.Arrange pieces of smoked salmon on top and add a pinch of watercress. Drizzle over a little olive oil and serve with a wedge of lemon."