In a large bowl, whisk together the gluten-free flour, 2 tablespoons sugar, yeast, and salt.
In a separate bowl, combine warm milk, ¼ cup melted butter, eggs, apple cider vinegar, and 1 teaspoon vanilla.
Add the wet ingredients to the dry ingredients and mix until a soft, slightly sticky dough forms.
Let the dough rest for 10 minutes to allow the flour to fully hydrate.
Prepare the coating by mixing 1 cup sugar and cinnamon in one bowl and placing ½ cup melted butter in another.
Using lightly oiled hands, pinch off small pieces of dough (about 1½ inches) and roll into balls.
Dip each ball in melted butter, then roll in the cinnamon-sugar mixture until fully coated. Arrange the coated balls in a greased bundt pan.
Cover the pan with plastic wrap and let rise in a warm place for about 45 minutes, until noticeably puffy.
Preheat your oven to 350°F (175°C).
Bake for 30-35 minutes until golden brown and a toothpick inserted in the center comes out clean. Tent with foil if needed to prevent over-browning.
Let cool in the pan for 5 minutes, then carefully invert onto a serving plate.
For optional glaze, mix powdered sugar, 2-3 tablespoons milk, and ½ teaspoon vanilla until smooth, then drizzle over warm bread.