Solo Poppy Seed Cake & Pastry Filling, 12.5-Oz (Pack of 6). Solo Poppy Seed Cake & Pastry Filling is ideal for incredible desserts! Making scrumptious desserts with Solo Fillings has never been easier.The finest European Poppy Seeds are sweetened with spices to make ready-to-use Solo Poppy Seed Filling, a true classic and the only choice for quick and easy desserts. Certified kosher. Solo Poppy Seed Cake & Pastry Filling is sold in a pack of six(6) cans with net 12.5 oz each.