Step 1 Preheat oven to 140°C. Spray a large flameproof, ovenproof baking dish with cooking oil and set over high heat. Cook beef, in batches, for 2 minutes, or until golden. Remove beef; set aside.
Step 2 Return dish to medium–high heat and spray with oil again. Cook onion and carrot, stirring occasionally, for 5 minutes, or until soft. Add garlic and button mushrooms; cook for 3 minutes, or until mushrooms are golden. Add flour and tomato paste; cook, stirring, for 1 minute. Return beef to dish and add red wine; simmer until mixture reduces by half.
Step 3 Add beef stock, Worcestershire sauce, potato and ½ cup water to dish; stir mixture to combine. Cover dish with lid or foil; bake for 1½ hours, or until meat is tender and sauce thickens.
Step 4 Increase oven heat to 200°C. Cut a round of pastry to make the pie lid, using the base of a 4-cup-capacity baking dish as a guide, and leaving an extra 1cm pastry border.
Step 5 Spoon beef and mushroom filling into dish and cover with pastry lid, pushing edges down around rim. Cut a slit in the top and spray with a light coating of cooking oil. Bake pie for 25–30 minutes, or until golden brown.
Step 6 Serve each quarter of pie with 2 cups salad greens.