In 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 81⁄2-inch round; set aside, covered with towel.

Heat 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 11⁄2 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 thoroughly heated.

Spoon vegetable mixture into ungreased 91⁄2-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.

Bake 25 to 30 minutes or until crust is golden brown.

Let stand 10 minutes before cutting.