Preheat your oven to 400F and line a baking sheet with parchment paper.
In a large microwave-safe bowl, combine the shredded mozzarella cheese and cream cheese. Microwave in 30-second intervals, stirring between each, until fully melted and smooth, about 1 to 2 minutes total.
Add the almond flour, egg, and baking powder to the melted cheese mixture. Stir vigorously with a spatula or knead with your hands until a uniform dough forms. If the dough gets sticky, wet your hands slightly.
Divide the dough into small pieces and roll each into a ball about 1 inch in diameter. Place them on the prepared baking sheet about 1 inch apart.
Bake for 12 to 14 minutes until the pretzel bites are golden brown on top and feel firm when lightly pressed.
Remove from the oven and immediately brush the tops with melted butter. Sprinkle generously with coarse sea salt and garlic powder if desired.
Let cool for 5 minutes before serving. These are best enjoyed warm with mustard or a low-carb cheese dip.
