- 6 (17- by 12-inch) phyllo sheets, thawed if frozen
- 1/2 stick (1/4 cup) unsalted butter, melted
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 3/4 cup whole milk
- 2 teaspoons Dijon mustard
- 2 large eggs, separated
- finely grated Parmigiano-Reggiano (1/2 cup)
- 5 oz soft mild goat cheese, crumbled (2/3 cup)
- 1 1/2 tablespoons cider vinegar
- 1 1/2 teaspoons Dijon mustard
- 1/4 teaspoon salt
- 5 tablespoons extra-virgin olive oil
- 8 oz frisée, torn into bite-size pieces (8 cups)
- 6 radishes, cut into very thin wedges
- 3 tablespoons chopped fresh chives
- Special equipment: a muffin pan with 12 (1/2- or 1/3-cup) muffin cups
- Preheat oven to 375°F.
- Cover stack of phyllo with 2 overlapping sheets of plastic wrap and a dampened kitchen towel. Put 1 phyllo sheet on a work surface and brush with some butter, then top with 2 more sheets of phyllo, brushing each with butter.
- Cut buttered stack into 6 (4 1/2-inch) squares with a sharp knife, trimming sides as needed. Line each of 6 muffin cups with a square. Make 6 more phyllo cups (4 are extra, in case of breakage) in same manner with remaining pastry sheets and butter.
- Bake cups in middle of oven until golden, about 8 minutes, then cool completely in pan on a rack.
- Increase oven temperature to 400°F.
- While cups are cooling, melt butter in a 3-quart heavy saucepan over moderately low heat, then whisk in flour. Cook roux, whisking, 3 minutes. Add milk in a stream, whisking, and bringto a boil, whisking. Reduce heat and simmer, whisking occasionally, 5 minutes. Remove from heat and whisk in mustard, yolks, and 1/4 cup Parmigiano-Reggiano until combined, then fold in goat cheese. (Cover surface of mixture with wax paper if not using immediately.)
- Beat egg whites in a large bowl with an electric mixer until they just hold stiff peaks. Fold one third of whites into sauce to lighten, then fold in remaining whites gently but thoroughly.
- Spoon batter into 8 phyllo cups and sprinkle with remaining Parmigiano-Reggiano. Bake in middle of oven until soufflés are puffed and golden, about 15 minutes.
- Whisk together vinegar, mustard, and salt in a bowl, then add oil in a slow stream, whisking until emulsified.
- Just before soufflés are ready, toss frisée and radishes in a large bowl with just enough dressing to coat. Mound salad onto 8 plates and sprinkle with chives, then make a small nest in center of each.
- Place a soufflé cup in each salad and serve immediately.