1 small shallot, finely diced
5 stems of parsley (stems only), coarsely chopped
4 black peppercorns
1 tablespoon plus 1 teaspoon cider vinegar
1 teaspoon espresso dissolved in 1/4 cup recently boiled water
1 tablespoon heavy cream
1/4 teaspoon granulated sugar
Fine sea salt
1 stick (8 tablespoons or 4 ounces) very cold unsalted butter, cut into small cubes, plus 1 tablespoon
12 to 16 large sea scallops
1. In a small saucepan, add the shallot, parsley stems, peppercorns, cider vinegar and espresso powder dissolved in the hot water. Bring to a simmer over medium heat and simmer until reduced to 2 teaspoons, about 10 minutes.
2. Whisk in the heavy cream, then begin adding the stick of cubed butter, about 3 small cubes at one time, whisking constantly. Add more butter only once the butter just added has melted into sauce. Once all the butter is incorporated, remove from heat, add sugar and season to taste with salt. Strain into a bowl and set aside.
3. Working quickly, melt the remaining tablespoon of butter in a heavy-bottomed 12-inch stainless steel skillet over medium-high heat until butter foams at the edges of the pan. Pat scallops dry on paper towels, and season lightly with the fine sea salt. Sear scallops 3 minutes on first side, until golden brown. Turn and sear 2 minutes on the reverse side.
4. Plate the dish with a puddle of beurre blanc in the center, with the scallops nestled on top. Serve immediately.