Mirdin is a software-design teaching company founded by James Koppel, an MIT-trained programming-language theorist whose course material is unusually rigorous about the theoretical underpinnings of software-design decisions — type theory, algebraic data structures, and the lambda-calculus foundations underneath modern languages.
The CourseFlix listing carries the Advanced Software Design Course by Mirdin. Material is paid and aimed at experienced software engineers ready to think about design at a much deeper level than framework idioms.