Are you channeling your best self with this comment? (If you're not sure, check out our Code of Conduct.)
Francesca is the former Assistant Editor of food52 and believes you can make anything out of farro.
That's a toughie! While we all think on it, have a look at the gluten-free baking options from our recent contest ... there may be no bagels, but oh are there plenty of tasty breakfast options that use flours your niece should be fine eating: http://www.food52.com/contests...
Here is a wonderful site for gluten free foods and the link to her recipe for bagels
Here is a glutinois recipe for bagels:
Now, for the 500 grams of flour, you can use Gluten Free Girl's formula for making an AP Gluten Free blend : http://glutenfreegirl.com...
Swap out the brown rice for another whole grain and the sweet white rice for another starch. Here is a chart that can help you with the swap. http://frannycakes.com/resources/gluten-free-flours/
You do need a scale for this, but they can be found inexpensively. Alternately, you could do the first recipe with a packaged blend like the one from King Arthur or Jules Nearly Normal.
You will also need to add about 1/2 teaspoon of xantham gum per cup of flour.
Hope this helps!