In your Settings > Permalink page, you would select the "Custom Permalink" radio button, and simply add:
/%postname%/ . This will make it so that when you click on the "reviews" tag, that it should only show "http://www.example.com/reviews" when you are on the Archive page for reviews.
HOWEVER, this may have adverse repercussions on the performance of for the rest of your site. It will drop all the nesting structure of all other post urls.
If you wanted to have the effect of just modifying the results for one custom taxonomy tag, ignore the above instructions, and create a custom page template for reviews, by doing the following:
Copy the Archives page from your theme directory, give it a new name like "Review-Page.php", then open it up and add at the top of the page
<?php /* Template Name: Review Page
Save this page and upload it to your theme directory.
From the WP admin panel, create a new Page (not post). Name it "Reviews". Set the Page Template (in the right column below the "Save" button) to "Review Page". Then save it. You don't really need to add anything in the content section.
What you've just done is create a custom page template and told it to open your archives when the Review page is opened from the front end.
There's only one other thing left to do and that is tell the custom page template to open the Reviews custom taxonomy. I don't know how to do that off the top of my head and I need to move on for the afternoon, but basically, you'll need to get the archive page that you've copied, the "Review-Page.php" that you created and tell it to only return results for the term "Recipe".
Anyone else want to jump in here and finish this up? Sorry, I'm still a little green around the edges. Hope this helps.