In a mixing bowl, combine 2 1/2 cups of the flour, 2 teaspoons of the salt and 1/4 teaspoon of the cayenne. Cut in the lard with a pastry blender until the mixture resembles coarse meal. Add the ice water and mix until the dough comes away from the sides of the bowl. Form the dough into a ball and cover with plastic wrap. Place in the refrigerator and chill for 1 hour. Preheat the oven to 350 degrees F. Remove the dough from the refrigerator and let sit for about 5 minutes. Lightly dust a work surface with the remaining flour. Roll the dough out into a 12-inch round about 1/4-inch thick. Fold the dough into fourths and place it in a 10-inch tart pan. Roll a wooden rolling pin over the pan to cut off the excess dough. Prick the bottom of the crust all over with a fork. In a medium saute pan, over medium heat, melt the butter. Add the onions. Season with salt and pepper. Saute for 1 minute. Add the mushrooms. Season with salt and pepper. Continue to saute for 3 to 4 minutes or until the mushrooms are wilted. Stir in the garlic and remove from the heat. Cool completely. In a mixing bowl, whisk the cream and eggs together. Season with 3/4 of a teaspoon of salt, pepper, hot pepper sauce, and Worcestershire sauce. Mix well. Pour the mushroom mixture into the pastry shell. Sprinkle the cheese over the mushrooms. Pour the cream mixture over the cheese. Bake until the center sets and the top is golden, about 55 minutes. Remove from the oven and let cool for 5 minutes before slicing to serve. In a mixing bowl, toss the pea shoots with the truffle oil. Season with salt and pepper. To serve, place a slice of the tart in the center of each plate. Garnish each with a pile of the pea shoots.