I always use tags and categories for my blogposts. They're very useful for easily finding or linking to blogposts about the same topic. For example, if you click on the tag "Star Trek", you can find all posts I've ever written about Star Trek. If you click on the tag "Star Trek Discovery", you'll only get my Star Trek Discovery reviews.
You separate tag phrases by comma, e.g. the tags for your apple cake recipe might look something like this: recipes, baking, apple cake, apples, cakes, food,
Of course, if you're not running a food blog, you might want to be less specific with your tags, e.g. I don't run recipes regularly, so I only tag them as "recipes" without any more detailed tags.