The phrase "more morsel" refers to wanting an additional small piece of food, but there are plenty of synonyms to use instead of this expression. "Another bite," "an extra nibble," and "an additional mouthful" are all alternatives that convey the same sentiment. "A supplementary crumb," "a bonus fragment," and "an added speck" are also options to use in place of "more morsel." It's essential to have a wide range of synonyms to use in your writing to avoid repetition, and these variations will provide some diversity when describing small pieces of food.