1Heat oven to 400°F. Remove pie crust from box; set aside.
2In 3-quart saucepan, melt butter, stirring constantly. Stir in flour. Cook, stirring constantly, until smooth and bubbly. Stir in soup, vegetables, chicken and thyme. Heat over high heat, stirring frequently, until mixture is hot and bubbly. Pour into ungreased 2-quart casserole.
3Unroll pie crust and place over top of casserole. Roll up outer 1-inch edge of crust so rolled crust edge fits inside edge of casserole; press crust lightly onto soup mixture. Cut several slits in crust to allow steam to escape.
4Bake 30 to 35 minutes or until crust is golden brown. Let stand 10 minutes before serving.