In a large pot, heat olive oil.

Coat the steak in the flour and shake off the excess. 

Fry the beef in the pot on all sides until golden brown. Remove from the pot and put aside. 

In the same pot, fry the onions until they are soft and transluscent. 

Add the rosemary, thyme, and garlic and fry for another 30 seconds. 

Pour the tomatoes into the pot with the beef stock. Add the steak back into the pot. 

Reduce the heat to a simmer and cook for 1-1/2 to 2 hours or until the beef is soft and tender. Keep an eye on the pot and add more beef stock if necessary, so that it covers the beef. 

Preheat the oven to 350°F. 

After the beef is finished cooking, season to taste with salt and pepper and place in an oven proof pie dish.  

In a small bowl, beat the egg with a fork. 

Brush the edges of the pie dish with the beaten egg and roll the puff pastry over the top. Trim the edge of the pastry and brush the top with the egg. 

Make a small incision in the center of the pie to allow the steam to escape. 

Place the pie in the oven and bake for 20-25 minutes, until the pastry is golden brown and crisp. 

Remove from oven and serve.