An hour or so ahead of time, set out the cream cheese to soften.
Preheat oven to 450 degrees F.
Meanwhile, heat an 8- or 9-inch cast iron or other skillet over medium-high heat. Melt the butter, add the shallots, and fry for 2 - 3 minutes. Fold in onion and garlic powder. Remove the pan from heat and set aside to cool slightly.
Once pan has cooled a bit, add the cream cheese (it may sizzle a little) and stir. Fold in the sour cream, hot sauce, roasted cauliflower, and lemon zest. (No need to over mix.) Top with the cheddar.