Vegetarian Wellington with Mushrooms and Buckwheat

Ingredients

• Filling

  • 1 lb (450 g) white mushrooms
  • 3 tbsp unsalted butter (see note)
  • 2 shallots, finely chopped
  • 2 garlic cloves, finely chopped
  • 3 thyme sprigs (optional)
  • 1/2 cup (100 g) white buckwheat groats, rinsed and drained
  • 1/2 cup (125 ml) dry white wine
  • 2 1/2 cups (625 ml) mushroom broth
  • 1/4 cup (20 g) panko breadcrumbs
  • 2 tbsp flat-leaf parsley, finely chopped
  • 2 to 4 large red Swiss chard leaves, stems removed and cut into small dice

• Flaky Shortcrust Pastry

  • 1 cup (150 g) unbleached all-purpose flour
  • 1/4 tsp salt
  • 1/2 cup (115 g) cold unsalted butter, thinly sliced
  • 1/3 cup (75 ml) ice water

• Egg Wash

  • 1 egg, lightly beaten (see note)

• Sauce

  • 1 package (12 g) dried morel mushrooms
  • 1 1/2 cups (375 ml) hot water
  • 2 shallots, finely chopped
  • 2 thyme sprigs (optional)
  • 3 tbsp unsalted butter
  • 1/4 cup (60 ml) dry white wine
  • 1 1/2 cups (375 ml) mushroom broth
  • 2 tbsp light toasted flour