Preheat oven to 400°. Heat oil in large saucepan over high heat.
Add onions and cook for 3 minutes or until soft.
Add steak to pan and cook for 4 minutes or until meat is seared (browned).
Add stock, wine, Worcestershire sauce and tomato paste. Reduce heat and simmer, uncovered for 50 minutes or until meat is tender.
Combine flour and water into a paste and stir into meat mixture. Bring mixture to boil and stir for 1 minute (it will have the consistency of melted chocolate).
Season to taste with salt and pepper, cool.
Pastry
Rollout pastry on a lightly floured surface until it is 1/8" thick.
Cut pastry so that it will have a slight overhang on the small pie tins (at least 8 oz. in capacity) or mini cocottes.
Assembly
Place filling in bases and top with formed pastry circles and crimp.
Want to get fancy? From pastry scraps, use pie cutters or cut out letters or numbers and place on top of pie.
Brush pie tops with egg and place pies in the oven.
Bake for 15-20 minutes or until pastry is puffed and golden.
Notes
To make these pies more interesting add sliced mushrooms when you add the flour and water. They will cook while the mixture is cooling.