Support for Drupal 7 is ending on 5 January 2025—it’s time to migrate to Drupal 10! Learn about the many benefits of Drupal 10 and find migration tools in our resource center.
Create a block with the following code
global $user;
print l("My Blog", "blog/" . $user->uid);
Thanks go to MichelleC and Richard Eriksson from this post.