Method

1. Heat a barbecue grill to high. Add muffins and cook on each side until golden.
2. To make hollandaise sauce, put egg yolks, 2 Tbsp of the vinegar, lemon juice and mustard in a heatproof bowl. Holding bowl slightly above grill, whisk until it thickens.
3. Put bowl on coiled tea towel on a flat surface, then slowly whisk in ghee. Season with salt.
4. Heat a wok burner or barbecue grill to high. Put water and remaining vinegar in a medium saucepan, then add to burner or grill. When small bubbles form, crack in eggs, one at a time, and cook for 4 minutes. Remove with a slotted spoon.

5. Arrange 2 muffin halves on a serving plate. Top each with salmon, egg and hollandaise sauce. Add chives to serve.