1In medium bowl, mix flour, salt, thyme and oil until all flour is moistened. Sprinkle with cold water, 1 tablespoon at a time, tossing with fork until all water is absorbed. Gather pastry into a ball. Place pastry between 2 sheets of waxed paper. With rolling pin, roll into 8 1/2-inch round; set aside, covered with towel.
2Heat oven to 425°F. In 12-inch skillet, melt butter over medium-high heat. Add mushrooms; cook 5 to 7 minutes, stirring frequently, until mushrooms are tender. Stir in 1 1/2 cups half-and-half and the sauce mix. Heat to boiling over medium-high heat, stirring constantly. Stir in vegetables. Cook 2 to 3 minutes, stirring frequently, until heated through.
3Spoon vegetable mixture into ungreased 9 1/2-inch deep-dish pie plate. Remove top waxed paper from crust; cut about 1-inch hole in center of crust. Carefully invert crust over filling; remove remaining waxed paper. Cut small slits in several places in crust. Brush crust with 1 teaspoon half-and-half.
4Bake 25 to 30 minutes or until crust is golden brown. Let stand 10 minutes before cutting.