Combine the crumbs and melted butter and pat into an 8 inch pie plate. Beat cheese until fluffy while adding sugar, lemon and vanilla. Add eggs one at a time beating thoroughly after each addition. Pour into crumb crust and bake 25 - 30 minutes in 325ºF. oven or until set. Combine the sour cream, butter and vanilla. Spoon over top of pie. Bake 10 minutes longer. Cool. Chill several hours before serving. If glaze is desired, chill can, just before serving spoon over pie slices.