diff --git a/lib/octodown/support/helpers.rb b/lib/octodown/support/helpers.rb
index 8302087..dc4a4f8 100644
--- a/lib/octodown/support/helpers.rb
+++ b/lib/octodown/support/helpers.rb
@@ -6,7 +6,7 @@ module Helpers
       # TODO: Find a better home for this logic
       def self.markdown_to_html(content, options, path)
         html = markdown_to_raw_html(content, options, path)
-        tmp = Octodown::Support::HTMLFile.new 'octodown'
+        tmp = Octodown::Support::HTMLFile.new ['octodown', '.html']
         tmp.persistent_write html
       end