Ingredients
Method
- Add 1.5 lbs fingerling potatoes to a medium pot and fill with water. Stop when the water has covered the potatoes by about 1 inch. Season with 1/4 cup salt, 3 tbsp sugar and 3 tbsp red wine vinegar. Bring to a rapid boil, then reduce to a gentle boil. Cook potatoes until fork tender, about 8-10 minutes.
- Strain the potatoes and set aside. Back in the pot, add 8 tbsp butter and heat on low. When the butter is melted, add 1/4 cup water to a 1 cup measuring cup, ideally one with a spout for easy pouring. Add 2-3 ice cubes and stir until cold.
- Remove ice cubes and slowly whisk in cold water into melted butter, a tablespoon at a time, until the sauce slightly thickens and coats the back of a spoon. You should only need about 3 tbsp of water. Once emulsified, whisk in 1 tbsp honey and 1 tbsp grainy mustard.
- Add the cooked potatoes to the butter sauce and toss to coat. Transfer to a serving platter and top with sliced cornichons.
Notes
If making ahead, keep the potatoes and the sauce separate until ready to serve. The sauce will keep in the pot, covered, on the lowest stove setting. However, if the sauce simmers rapidly for too long it will split and won't come back together, so aim to keep it warm but not simmering.
If the sauce is not emulsifying, add more water followed by a bit more cold butter (about a tablespoon of each at a time) and continue whisking until you get there.