To make the berbere butter, cream the butter in a small bowl. Add the spice, lemon zest and juice, season with salt and pepper, and mix well. Form into a long roll, then cover with clingfilm and put it in the freezer for 15 minutes or in the fridge for 1 hour to firm up.
Preheat the oven to 100°C/Fan 80°C/Gas ¼, line a baking tray with foil and put it in the oven to keep the pancakes warm while you make them. Put the flour, spring onions, milk and eggs in a blender or food processor and whizz to make a batter. Add the Swiss chard and garlic and whizz briefly so there are still some longish strands of green leaves. Pour into a bowl and stir in the herbs, nutmeg and seasoning.
Place a large, non-stick frying pan over a medium heat. Smear generously with oil using kitchen paper, and heat until hot enough that a droplet of batter sizzles. Add 2 tablespoons of the batter to make small farçous, or you can make several pan-sized ones instead. Cook for 3 minutes or until lightly browned underneath and turning frilly at the edges. Flip over and cook for a further 2 minutes. Keep warm. Repeat with the remaining batter, adding more oil to the pan as necessary. Serve with the lemon, berbere butter.