Williams-Sonoma Bundt Tunnel (Bundt Cake Accessory) Williams-Sonoma Bundt Tunnel (Bundt Cake Accessory) Non-stick baking ring creates ready-to-fill tunnels inside homemade Bundt cakes! Manufactured by NordicWare for Williams-Sonoma This Bundt Cake Tunnel is no longer available from Williams-Sonoma Brand new in original box! Includes instruction and recipe booklet!