These are a kind of sushi-style take on a classic combination of smoked salmon and crème fraîche inside a pancake. You can make them up the day before, keep them in the fridge wrapped in cling film, then slice them up at the last minute. They look great if you serve them up-ended, like sushi-rolls, on a rectangular or square plate with the dip in a little bowl. You could use mustard mayo or even horseradish sauce instead of the vinaigrette dip if you like.
Crack the eggs in a mixing bowl, then add the flour to the bowl so it sits in a pile to one side of the eggs. Gently start mixing the eggs with a whisk, then gradually whisk the flour in, little by little, until it’s all incorporated. If it gets a bit thick, add some of the milk to loosen it up. Once all the flour is mixed in, add the rest of the milk, 2 tablespoons of oil and a good pinch of salt. Leave for at least an hour before using.
Heat a large non-stick frying pan and melt a knob of butter in it. Pour in a ladleful of batter, swirl the pan around, then pour any loose batter back into the bowl it came from. You should be left with a thin pancake stuck to the pan. Let it cook for a minute or so, flip it over for 30 seconds and then slide it out on to a plate. Repeat until all your batter is used. (It should make about five, so you could use the remainder for breakfast). Let the pancakes cool.
Make a rectangle of double thickness cling film about 40cm x 15cm and lay two pancakes on it side by side, slightly overlapping. Spread them with a thin layer of crème fraîche, lay most of the chives on top, season well with pepper and place a layer of smoked salmon over the top. Use the cling film on one of the long sides of the rectangle to roll the pancakes up tightly like a Swiss roll. Re-wrap in cling film and leave for at least half an hour in the fridge to firm up before slicing into inch lengths and serving with a dip made from the rest of the oil, the lemon juice and salt and pepper. Sprinkle with the remaining chives before serving.