Markdown - StackEdit's HTML export template with highlighting by using Prettify or Highlight.js and personalized markDown.css

StackEdit is a Markdown Extra editor with MathJax (to display formulas using TeX Math syntax, see HERE if you are interested to show them on Blogger) and Prettify or highlight.js (for code highlighting) support.
It is a wonderful option when it comes to publish some HTML, even with a custom CSS!

Markdown is a text-to-HTML conversion tool for web writers. Markdown allows you to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML).