Niman Ranch Burgers with Caramelized Onions

Well....first off....I did not order Niman Ranch beef. There are great places that sell highest quality grass-fed beef right here in the great state of Texas. One of them is Burgundy Pasture Beef. I order all of my beef from them at burgundypasturebeef.com. It is exceptionally tasty and 'clean'! I thawed some of the ground chuck for this recipe.
The meat was easy to mix with the other ingredients and came together as patties nicely. My husband did the grilling. He just grilled burgers as he always does and not particularly the way that she wrote in the recipe. I cooked the onions as he got the burgers done.
The only alteration I made in the caramelized onion recipe was to substitute marsala wine vinegar for sherry wine vinegar. The only sherry wine vinegar I could find was $12 a bottle. And I just wasn't going there. I've never seen another recipe that called for it and it was very difficult to find. It was an easy 'no'!
The onions took at least 15 minutes more than the recipe called for. If I were to do it again, and I think I will, then I would cook them at a bit higher heat and just watch them closely. I did like the step that let them sweat in the beginning. This seemed to work well.
When the pieces were complete, I assembled the burgers just as instructed. And they. were. fabulous. I mean, I'm a meat, bread, and ketchup kind of girl. So burgers on an english muffin with mayo and the meat with dijon in it....that was a stretch for me. But I loved them. My husband loved them. My children loved them.
I wish that this were the end of my post....but no....after my sweet, 4 year old ate nearly an entire $4.50 per pound hamburger....saying 'oh, its yummy'....she then agreed to try some onions....she swallowed them....and then proceeded to puke her entire dinner up all over the middle of the table as the rest of us were sitting there. Chewed up burger mixed with milk...let me tell you....its not appetizing. But after a full scale clean-up and a settling of the kiddo....my husband and I both returned to the table to polish off the rest of our meals. They were that good, people.