I also found out that Lipton's Onion Soup mix is no longer GF, it now lists barley as an ingredient on the label. I read it for myself when purchasing some at Sam's Club, and other's are discovering it too.
So, getting ready to travel to visit family this weekend, I picked up a (spendier) box of GF Rice Crispies and made myself some dry onion soup mix using this recipe. I was wondering about the trivial amount of sugar called for in the recipe, but my rule of thumb is to follow a recipe exactly the first time I make it (from there on, I substitute/omit/etc. as I feel inclined). I didn't have bullion powder so I put bullion cubes and the other spices/sugar into my food processor to chop/mix. I added the dried onions last and only gave it a few pulses to mix them. It turned out really well and did have more flavor than the boxed variety, so I used 4 T (rather than the recommended 5 T) in place of one envelope of Lipton's dried onion soup mix in my recipe. I will definitely be making it again and again!