Headings between listitems?

What's a good way to insert a heading between items in a single ordered 
list?

I have a longish numbered list, and I would like to group some of the 
list items underneath unstructured headings with zero indent.

For example:

Spread the peanut butter:
1. Open jar of peanut butter.
2. Use knife to spread PB on one piece of bread.

Spread the jelly:
3. Open jar of jelly.
4. ... and so forth

Right now, I'm getting the results I want by marking the list as a 
series of ordered lists with continued numbering, and tagging the 
headings as titles. But that technique offends my structure 
sensibilities, since it's really all the same list.

Regards,
Mike O.