In a large skillet, saute onion and peppers in oil for 3 minutes. Add garlic; cook 1 minute longer. Stir in the beef, potatoes, soup, corn, mushrooms, Worcestershire sauce, salt and pepper. Bring to a boil. Reduce heat; cover and simmer for 10 minutes.
For pastry, combine flour and salt in a large bowl. Cut in shortening until crumbly; sprinkle with onion. Gradually add water, tossing with a fork until dough forms a ball.
Divide dough in half so that one ball is slightly larger than the other. On a lightly floured surface, roll out larger ball to fit a 9-in. deep-dish pie plate.
Transfer pastry to plate; trim even with edge. Add filling. Roll out remaining pastry to fit top of pie; place over filling. Trim, seal and flute edges. Cut slits in top.
Bake at 375° for 45-50 minutes or until filling is bubbly and crust is golden brown. Let stand for 15 minutes before cutting.