Ingredients :

• Ground beef — Get 15-20% fat content. Extra-lean beef dries out during cooking and lacks character in a filling. Fat is what binds the filling and gives it depth once simmered.
• Cold butter — Literally the key to the pastry. It must come out of the refrigerator 5 minutes before, no more. Those small pieces that remain visible in the flour create steam pockets during baking—hence the flakiness. Room temperature butter, and you get a shoe sole.
• Worcestershire sauce — Only one tablespoon, but it makes all the difference. It brings an umami depth that you couldn’t identify blindly, but whose absence you would notice. Lea & Perrins if you have the choice.
• Tomato paste — Not tomato sauce. Two spoons that give the filling a mahogany color and an incomparable density of flavor. Sauté it for 30 seconds in the pan before adding the broth—the aroma changes completely.