Avid Writer

Hello, I am working on a children's fiction novel and my genetics are a bit rusty, so I would like to receive help regarding inherited traits. In the narrative, I would like for two traits to produce three outcomes. Consider the traits as F or E. Then, children from an F and an E parent would have F, or E, and very rarely, FE. Taking away dominance and recession, how do I make this work? Punnett Squares arent helping but I may be doing something wrong. Get in touch!