See this thread for ideas
You can access the first of last post of the site.posts
object. You can then make a modified layout or just put all the logic in your home index page.
Depending on what sort of content you want to display this will vary. But at its most basic level this would output the latest post’s title and body content… without looping… which is good for your build time.
<h1>{{ site.posts.last.title }}</h1>
{{ site.posts.last.content }}