Tart cherries, nutty walnut ficelle, and floral, full-bodied sheep's milk (like Pyrenees Brebis) come together for this vegetarian- and picnic-friendly sandwich.
Put shallots and butter into a heavy medium saucepan over medium heat. Cook until shallots begin to caramelize and turn golden brown, about 10 minutes.
Stir in frozen and dried cherries. Cook, stirring occasionally, until mixture has thickened, 18 to 20 minutes (if cherries are not breaking down, crush with a potato masher). Stir in vinegar. Remove from heat; let cool completely.
Meanwhile, finely grind walnuts in a food processor. Add oil; process until mixture forms a thick paste.
Spread 1/3 cup shallot-cherry confit on bottom half of ficelle. Spread 1/4 cup walnut paste on top half of ficelle. Layer cheese over confit. Cut the sandwich into 4-inch pieces; discard ends. Wrap each sandwich in parchment paper.