3 leeks, sliced
1 red onion, finely sliced
2 Tbsp dried tarragon
1/2 cup white wine
1 tsp salt
1 tsp black pepper
2 puff pastry sheets, thawed
Flour, for dusting surface
1 egg mixed with 2 tsp water
3-lb salmon fillet, skin removed
Dijon whipped cream
1. Preheat oven to 350 degrees.
2. Melt the butter in a large skillet over medium heat. Add leeks, onion, and tarragon. Saute about 10 minutes, until onion is soft. Add wine. Raise heat to high and bring to a boil. Let the liquid cook off. Add salt and pepper. Remove from heat and let cool.
3. Unfold 1 pastry sheet and lay it on a lightly floured surface. Brush 1 edge with egg wash and overlap the other sheet by 2 inches. Roll it out until it's big enough to fold around the salmon.
4. Spoon the leek mixture down the center of the pastry, place the salmon on top of the leeks, and fold the pastry over the salmon. Spread egg wash on edges to seal and press well. Place seam side down on a piece of paper. Brush top with egg wash.
5. Cook 30-40 minutes, until puffed and golden brown. Let sit 15 minutes before slicing. Top with Dijon whipped cream.
Dijon whipped cream: 1 cup heavy cream, 1 Tbsp Dijon mustard, 1 tsp salt, 1/2 tsp white pepper. Whip cream until soft peaks form. Add mustard, salt, and pepper and beat until stiff peaks form. Refrigerate.