Creating and updateable block on home page of site
Drupal allows a node to be marked as &quot;Promoted to front page&quot; when editing the page (it's at the bottom, under &quot;Publishing options&quot;).
You can make your block from a View

Enable the Views module.
Add a new view admin/structure/views/add
Create a block (untick create a page)
Click &quot;Continue &amp; edit&quot;
Add a filter by &quot;Promoted to front page&quot;
Alter &quot;Use pager&quot; to display 1 item.
You should already have a sort by post date.
Save changes.
Add the block to your home page (it sounds like you already know how to do this, but ask if not).

This view will show the most recent item with promoted to front page set.