Barbacoa beef is not especially spicy, but it has just enough heat that small children probably won't enjoy it. I used to be afraid to cook anything even remotely spicy for my family. I hated the thought of my kids spitting out good food, and I hated the thought of cooking a separate meal for them even more. But eventually I figured out something pretty obvious. That when I make things like this, I can just leave off the spicy ingredients until I've plated everything, then add it on the grown up plates only (you can read more of my tips for picky eaters that I learned through YEARS of trial and error). In this case, omit the chipotles. If you leave them off, the flavor is unbelievably mild. Even my baby will eat it! I still want the chipotle flavor in my meal, so I dice and saute the peppers and then add them directly to my portion.