I wasn't going to suggest this because it could be a bit tedious, but it's a lot less tedious than entering the recipe titles on a spreadsheet and it's a solution that stays within EYB, so:
Bookmark all the recipes you haven't made yet; the good news is that there are only 140 recipes total in the book. Use a bookmark that begins with a letter that none of your other bookmarks begin with -- e.g. 'Yet to make FRL', so that as you read down the recipe listings you just have to click the 'add Bookmark' symbol, type Y, and click 'Save'. {To EYB developers: Repetitive bookmark additions like this are why I wish users could just hit 'enter' to Save after selecting a bookmark, rather than having to move hands off the keyboard to mouse-click on 'Save'...}
As you make each recipe you apply whatever Bookmark you've chosen for that, as you've been doing, and remove the Yet to make bookmark.
When you're looking at the recipe listings for A Free-Range Life, clicking on 'Yet to make FRL' will show you your to-do list, and you can sort the list alphabetically, reverse alphabetically, or by Buzz (notes) or Ratings (stars), as well as the default Book Order. You can also view the list via your Bookmarks, or by viewing your Bookshelf's Recipes and choosing 'Yet to make FRL' in the 'Show only Recipes..' dropdown menu. <--Sort options with this last method are not quite the same as those in the book's recipe listing.