Brown the meat in a skillet over low heat until thoroughly cooked. Drain off any remaining fat. Crumble the beef cubes and add them along with 1 1/2 cups of water, pepper, salt, and nutmeg. Let it boil, then reduce the heat.

Cover the skillet, then simmer for about 20 minutes, stirring occasionally.

Add 1/4 cup of water with 2 tablespoons of flour and mix thoroughly. Pour this to the meat, then stir until well combined. Return the meat to the heat and stir until the mixture thickens. Add the soy sauce and stir well.

Simmer (uncovered) for about 5 or 10 minutes, then remove from heat and allow it to cool before pouring into the pie shell. Roll out the thawed puff pastry on a flour-dusted surface and cut the pastry to fit over the pie. Mix the egg yolk and water together then brush over the top of the pie, then bake the meat pie at 400 degrees Fahrenheit for about 5 minutes, or until the pie crust is golden brown.

Reduce to 350 degrees Fahrenheit and cook for an additional 10 minutes.