Hi! You can try making hamster porridge, have attached the instructions as a photo. You can make a month's worth each batch, freeze and defrost every night as needed.
My hamster was given hamster porridge by her fosterer as a post-natal supplement and I have continued feeding it to her nightly as she is used to it. Not sure which country you are in, but in Singapore we have Paws of Porridge -
Welcome to Paws of Porridge! - Home-cooked porridge for hamsters. You can look on there to get inspiration for the different types of porridge you may want to make for your hamster.