Dairy-free beef Stroganoff

This is an adaptation of Chef John's Beef Stroganoff recipe, omitting the butter, using shallots in place of the onion, increasing the quantity — and roasting — the garlic, and making use of Tofutti's Sour Supreme in place of the sour cream.

This isn't the first time I've made it and it won't be the last. Also, it's one of those dishes which magically tastes even more awesome on the second day.