Steak and Stilton Pie

1/4 C olive oil
1 1/4 lb beef chuck, cut into 1" cubes
3 cloves garlic, finely chopped
2 large yellow onions, sliced
2 ribs celery, thickly sliced
2 small carrots, thickly sliced
2 tbsp minced rosemary
1 12 oz bottle stout beer
1/4 C flour
2 C beef stock
2 tsp. mustard powder
1 bay leaf
1 tbsp unsalted butter
10 oz mushrooms, quartered
6 oz English Stilton, crumbled
1 10 oz package frozen peas
1 14 oz package puff pastry
1 egg, lightly beaten

1. Heat oil in an 8 qt saucepan over medium-high heat.  Season beef with salt and pepper, and cook until browned, 10-12 minutes; transfer to a bowl.  Add garlic onions, celery, carrots, and rosemary to pan; cook until soft, 10-12 minutes.  Add beer; cook until almost dry, 18-20 minutes.  Add flour; cook, stirring, until smooth.  Return beef to pan along with stock, mustard, and bay leaf; bring to a simmer over medium-low heat.  Cook, coverd partially, until beef is barely tender, about 1 1/2 hours; set aside.  Heat butter in a 10" skillet over high heat.  Add mushrooms; cook, stirring, until browned all over, about 8 minutes; stir into beef mixture along with cheese and peas.

2. Heat over to 375 F.  Divide beef mixture among four 6" pie tins  (12 oz. each).  Roll pastry into a 14: square; cut out four 6" circles.  Brush tin edges with egg; place 1 circle over each; press to seal.  Cut slits into pastry; brush with egg.  Bake until browned, about 40 minutes.