models.cs

// Author.cs
public class Author
{
    public int Id { get; protected set; }
    public string FirstName { get; protected set; }
    public string LastName { get; protected set; }
    private readonly List<Blog> _blogs = new List<Blog>();
    public IReadOnlyCollection<Blog> Blogs => _blogs;
}

// Blog.cs
public class Blog
{
    public int Id { get; protected set; }
    public string Title { get; protected set; }
    public string Content { get; protected set; }
    public int AuthorId { get; protected set; }
    public Author Author { get; protected set; }
}