Answering the question
As your markdown reads now it is hard to do because there is nothing in the markdown that makes it possible to extract parts of it. If you don't want to change your markdown format (or use something more suited for this) then you can do it client side with a bit of javascript (or maybe css). Put the "something else" part in the end of your generated code with an id that you find with javascript. The move it to the place where you want it. If you always have a header named Ingredients you should be able to query for that element and insert you other content before it. If you can stand wrapping you markdown parts with divs then it may be a bit more failsafe.
Better alternative
I don't know about jekyll but nanoc that I am using has a header that you put in your source file that you can extract information from in your layout. I would put title and description in there and then pull them out in my layout. The nanoc markdown file would look like this:
---
title: Very nice carrot soup
kind: recipe
created_at: 2013-10-03 1:59:00
author: fredrik
description: This is some really good carrot soup.....
---
### Ingredients ###
* carrots
* celery
* lentils
### Cooking ###
Boil some water. And eat it with all Ingredients
and the layout would extract the title and the author. Snippet:
<div class="head">
<h1><%= @item[:title] %></h1>
<p><%= @item[:description] %></p>
</div>
<%= add_some_more_stuff %>
<%= yield %>
You can probably do something similar with jekyll.