The problem with using <Hx> tags in the recipe is that EasyRecipe has no knowledge of the structure of the post as a whole and can therefore can’t make a judgement as to what would necessarily be an appropriate heading tag to use. It’s a moot point anyway because recipe elements are already <i>precisely</i> marked up by EasyRecipe anyway – search engines already know exactly where the recipe title is for example. It won’t need a heading tag as a hint that the words in a recipe title are important.
However with EasyRecipe Plus, it’s a relatively easy task to create a custom template (that won’t be overwritten by plugin updates) where you can edit the underlying HTML and create a structure that is totally different from the standard EasyRecipe templates.