Add the white sugar to the bowl of a stand mixer (or large mixing bowl if you prefer to knead by hand) and pour warm milk over. Stir to combine. Sprinkle the yeast over and set aside until bubbly or frothy; you should see a sort of film on the top of the mixture at least. This will take about 5 minutes.
Add the melted butter (About 110º F; warm to the touch but not hot) to the yeast mixture. Stir in whisked eggs and apple cider vinegar. Add in gluten-free flour, baking powder, salt, and xantham gum if your gluten-free flour does not contain it (See Note). Attach the bread hook to the mixer and mix on medium speed for about 5 minutes or until dough pulls away from sides of the bowl and is soft. It should not feel dry but a bit sticky. See Note to mix by hand.
Lightly oil a large mixing bowl and transfer dough to bowl. Cover and place in a warm spot. Let rise 1 hour. If your spot is cooler, it may take a little longer to rise, but the dough should be a bit puffier and should leave an indentation when poked. It will not double in size.
Meanwhile, make the cinnamon filling. In a medium bowl, add all ingredients and use a fork to mix very well. Alternately, beat all ingredients together with a stand mixer and paddle attachment.
Preheat oven to 350º F. Lightly coat a 9x13” baking dish with softened butter or cooking spray.
Cut a piece of parchment paper to about 12x18” and lay on the counter. Scrape the dough on top. Press the dough to fit the parchment sheet; the dough should be about 12x16” as well. It’s OK if it doesn’t quite fit the entire sheet.
Evenly spread the cinnamon filling on the rectangle of dough, leaving ½” bare at one end (short side, not long side).
Carefully, use the parchment sheet to begin tightly rolling the dough. Use the parchment to fold over the first 1” or so of the short side with filling all the way to the edge. Continue rolling the dough by folding the parchment over to the other side. It will roll naturally.
Cut the roll into 12 equal pieces. Place evenly into baking dish and bake 25-30 minutes. They will not puff up like cinnamon rolls with gluten in them but will become a bit fuller and should be a little golden brown. Do not overbake!
Meanwhile, make your cream cheese frosting. Add cream cheese and butter to the bowl of a stand mixer or a large mixing bowl and beat until completely combined. Cream cheese should be totally smooth with no solid lumps. Add in powdered sugar, vanilla extract, and salt; beat on medium speed until combined.
When cinnamon rolls are finished baking, remove from the oven and let stand 10 minutes before slathering tops with cream cheese frosting (A butter knife or offset spatula work well). Serve with additional cream cheese frosting.