Preheat the oven to 400 degrees F.
In a large skillet, cook the beef, stirring, over high heat until no longer pink, about 5 minutes. Add the onions, garlic, Essence, crushed red pepper and 1/4 teaspoon of the salt and cook, stirring, until the onions are soft and lightly caramelized, about 7 minutes. Add the tomato paste and heavy cream and cook until the cream is evaporated, 1 to 2 minutes. Remove from the heat and spread on a plate to cool.
In a large skillet, melt the butter over medium-high heat. Add the mushrooms, thyme, Worcestershire and remaining 1/4 teaspoon salt and cook, stirring often, until most of the liquid has evaporated, 8 to 10 minutes. Remove from the heat and spread on a plate to cool.
In a small bowl, beat the egg and water to make an egg wash.
On a lightly floured surface, 1 at a time, roll the puff pastry sheets to an 1/8-inch thickness, about 11 inches square. Cut each sheet into 2 rectangles. Spread 1/4 of the cooled mashed potatoes along the lower third of the pastry, leaving a 1-inch border on 3 sides. Top with the beef and the mushrooms, then sprinkle the Gouda cubes over the top. Brush the sides with egg wash and fold the pastry over the filling to completely enclose. Press to seal the edges and with the tines of a fork, press to seal tightly. Transfer to a large baking sheet and paint with the egg wash. Cut 5 small steam vents in the top of the pastry. Repeat with remaining ingredients.
Bake until starting to turn golden brown, 15 to 16 minutes. Sprinkle the top with the cheese and bake until the pastry is golden brown and the cheese is melted, about 4 minutes.
Remove from the oven and let rest for 5 minutes. Transfer to a large serving platter, slice and serve hot.
Yield: 12 to 14 servings