_header_block.html.erb

<div id="header_block">
  <div id="header_block_title"><%= title %></div>
  <div id="header_block_content"><%= content %></div>
</div>

<!--

call it with:

<%= render 'header_block', title: "Something", content: "A bit more" %>
-->

helper.rb

def header_block(title, content)
  content_tag :div, header_block_title(title)+header_block_content(content), id: 'header_block'
end

def header_block_title(title)
  content_tag :div, title, id: 'header_block_title'
end

def header_block_content(content)
  content_tag :div, content, id: 'header_block_content'
end