Preparation

• In the saucepan cook the onion and the fennel bulb in 2 tablespoons of the butter over moderate heat, stirring, until the vegetables are softened, stir in the flour, and cook the mixture, stirring, for 1 minute. Add the milk and Pernod and cook the mixture, stirring, for 3 minutes. (The mixture will be very thick.) Stir the fennel mixture into the spinach with 1/2 cup of the Parmesan and salt and pepper to taste. The filling may be made 1 day in advance and kept covered and chilled.
  Season the salmon fillet with salt, pepper and lemon juice.
  In a small bowl stir together 2 tablespoons Parmesan and the bread crumbs.
  Preheat the oven to 375°F. In a small saucepan melt the remaining 5 tablespoons butter. On a work surface arrange two 20-inch-long sheets of wax paper with the long sides slightly overlapping and facing you. Put 1 sheet of the phyllo on the wax paper, brush it with some of the butter, and sprinkle it with about 2 teaspoons of the Parmesan crumbs. On this, layer, brush, and sprinkle 4 more sheets of the phyllo in the same manner and lay the sixth sheet on top.
  Spread the spinach filling in a 3-inch-wide strip, mounding it on the phyllo 4 inches above the near long side, leaving a 2-inch border at each end, and arrange the salmon on top, pressing it gently into the filling. Using the wax paper as a guide, lift the bottom 4 inches of the pastry over the filling, fold in the ends, and roll up the strudel tightly. Transfer the strudel carefully, seam side down, to a lightly buttered baking sheet, brush it with the remaining butter, and bake it in the lower third of the oven for 30 to 40 minutes, or until it is golden. Let the strudel cool to warm on the baking sheet on a rack. Serve the strudel warm, cut into 1-inch slices with a serrated knife, with the lemon wedges.