- 1 pound small new potatoes
- 1 fresh or dried bay leaf
- 1 bunch of watercress (about 7 ounces)
- 2½ cups fish stock or vegetable stock or low-sodium broth
- ¼ cup extra virgin olive oil
- Kosher salt
- 4 tablespoons unsalted butter
- 1 stalk new green garlic
- 4 to 8 petrale sole, lemon sole, or flounder fillets (about 1½ pounds total)
- Freshly ground black pepper
- Scrub the potatoes well and place them in a medium saucepan with the bay leaf. Cover with salted cold water and bring to a boil over medium-high heat. Reduce the heat and simmer so the skins will stay intact and the potatoes won’t become waterlogged. Cook the potatoes until they are tender and can be easily pierced with a knife, about 30 minutes. Drain the potatoes and let cool. When they are cool enough to handle, peel the potatoes using a paring knife and cut them in half. Set aside.
- Remove and discard any thick stems from the watercress. Bring a pot of salted water to a boil and prepare a large bowl of ice water. Add the watercress to the boiling water and cook for about 1 minute, until tender. Plunge the watercress into the ice water to stop the cooking. When cool, squeeze out the water and put the watercress in a blender. Puree the watercress, adding up to ½ cup of the stock to help it along. When the mixture is the consistency of pesto, slowly pour in the olive oil, blending until well mixed. Add salt to taste and set aside.
- Trim off and discard the green top from the green garlic. Split the remaining section in half lengthwise. Rinse under cold running water to remove any dirt particles. Cut across on a slant to slice the garlic into thin shards.
- To make the poaching liquid for the sole, melt the butter in a large skillet over medium heat. Add the green garlic and a pinch of salt. Cook, stirring, until fragrant, about 1 minute. Add the remaining stock and swirl to combine. Bring the stock to a boil, then reduce the heat and simmer for about 2 minutes to allow the flavors to meld.
- In the meantime, put the watercress puree in a small pot and set over low heat to warm, stirring occasionally.
- Pat the sole fillets dry with a paper towel and season with salt and pepper. Gently lay each sole fillet into the poaching liquid and cook until the fish flakes, 1 to 2 minutes per side. Arrange the fish on 4 warmed plates and return the pan to the heat. Add the potatoes to the pan and swirl to coat the potatoes with the sauce. Raise the heat to high and cook until the sauce is thick enough to coat the back of a spoon and the potatoes are warm.
- Divide the potatoes among the plates and spoon the sauce on top, being sure each portion includes some green garlic shards. Spoon the warmed watercress puree around the fish. Serve immediately.