Vegetarian pie with wild mushrooms from the Big Green Egg

Ingredients

• 275 g cold butter + soft butter for greasing
• 500 g flour, plus extra for dusting
• 5 g fine sea salt
• 150 ml water
• 200 ml whipping cream
• 200 ml water
• 50 ml soy sauce
• 50 g dried porcini mushrooms
• 600 g mixed wild mushrooms
• ½ celeriac
• 1 leek
• 2 white onions
• 1 clove of garlic
• 50 g butter
• 1 tsp Madras curry powder
• 4 tbsp flour
• 1 egg yolk