This release for the Related Product Posts feature of Pro Blogger provides the ability to use a keyword from a text field or metafield as both a post filter or part of the matching criteria used to find blog posts relevant to the product.
Adding the word 'Recipe' and setting the Match with Keyword set to 'No' means that a Post must contain the word Recipe in its tilte or tags but that doesnt mean it is by default a match. Only that it must contain this word to be considered.
This way you will only show recipe posts but not ones that aren't relevant to the product.
Adding the word 'Recipe' and setting the Match with Keyword set to 'Yes' means that a Post must contain the word Recipe in its tilte or tags and if it does it will also be considered relevant for display.
This way all recipe posts are considered matches and will be sorted for relevancy.