Dough: Combine milk, yeast, and 1 Tbsp. sugar in a large mixing bowl. Set aside until foamy, 5 minutes. Whisk in egg and melted butter.In a separate bowl, mix together 1/2 cup sugar, gluten-free flour, baking powder, and salt. Add to yeast mixture and stir with a spoon until dough comes together. (Note: do not knead the dough, but mix until the dough becomes a fully incorporated mass.)Cover bowl with a towel and put in a warm place to rest for 50 minutes.Grease a 9-inch round cake pan. Lay a large piece of parchment paper on the counter and flour well with gluten-free flour. Dump dough onto surface and roll out into a 10- x 15-inch rectangle, with the longest side closest to you. 

Filling: Mix brown sugar, softened butter, and ground cinnamon in a small bowl until completely combined. Evenly spread filling across dough surface, leaving a one inch border along the top long side of the rectangleUse the parchment paper to roll the dough tightly into a log, starting from the long side closest to you. (Note: the dough will be slightly crumbly, so roll gently.) Once rolled, press the seam to seal it.Cut off 1/2 inch from each of the ends. Slice the log every 1 inch. Gently place each circle of dough into the pan with the swirl-pattern facing up. Cover with towel and rest for 20 minutes.

Preheat oven to 350°F. Brush the surface of the cinnamon rolls with melted butter, and bake until golden brown and until a toothpick inserted comes out clean, 25-30 minutes.

Cream Cheese Frosting: Beat cream cheese, butter, powdered sugar, vanilla, and salt in a stand mixer until smooth and light, about 2 minutes.Spread Cream Cheese Frosting over cinnamon rolls before serving.