Let's cook.
Preheat your waffle iron according to the manufacturer's instructions. Lightly grease if necessary.
In a medium bowl, whisk together the milk, vegetable oil, and salt until well combined.
Add the tapioca flour to the liquid mixture and whisk until a smooth batter forms. It will be quite thick.
Crack in the large egg and whisk vigorously until fully incorporated and the batter is uniform.
Stir in the shredded mozzarella cheese until evenly distributed throughout the batter.
Pour about 1/2 cup of batter onto the preheated waffle iron for each waffle, or enough to cover the grids without overflowing.
Close the waffle iron and cook for 4-6 minutes, or until the waffles are golden brown and crispy on the outside, and cooked through.
Carefully remove the cooked waffles from the iron and serve immediately. Repeat with the remaining batter.
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