Place the cast-iron skillet on the stove over medium heat. Warm the skillet then add the ground beef. Break the beef into small pieces as it cooks; about 10-12 minutes.

Preheat the oven to 375 degrees.

While the beef is browning, make the dairy-free cream-of-soup. In a small saucepan add the water, cassava flour, arrowroot powder, sea salt, onion powder, garlic powder, and ground black pepper. Whisk together. Over medium heat, bring the cream to a boil. Reduce heat to low and let cook for about 2 minutes to thicken; about 2 minutes. Remove from the heat.

Add the cream-of-soup to the browned ground beef and stir. Add the frozen mixed vegetables, stir into the mixture. Line the top of the mixture with the frozen tator tots.

Place the cast-iron skillet in the oven and let bake for 20 minutes. The tator tot hotdish is ready when the mixture is bubbling and the tots are golden brown. Remove from the oven and serve.