Previously, one of my favorite ramen was posted. Marutama ramen is another of my favorite. Marutama has been in Singapore longer than most Japanese specialty ramen restaurants. Their soup base also uses chicken. They make very good ajitsuke tamago (molten/ lava egg, ie eggs with creamy yolk center).
There are options to add negi (spring onions), aosa (Sea lettuce), ajitsuke tamago, chashu (pork belly slices), kakuni (Japanese braised pork), etc… I always like aosa, and marutama is the only ramen place which offers that. For ramen, one can also choose from the original marutama ramen, karashi ramen, aka ramen, tan men, etc… See more of the menu at the link provided.