Add ½ cup melted unsalted butter (cooled to 110°F), 2 whisked eggs, and 1 teaspoon apple cider vinegar directly into stand mixer bowl with activated yeast mixture. Stir to combine everything together.
Add 3¼ cups all-purpose flour, ¼ cup cocoa powder, 1 teaspoon red gel food coloring, 2 teaspoons baking powder, and ¼ teaspoon salt directly into same bowl.
Attach dough hook to stand mixer and mix on medium speed 5 minutes until dough pulls away from sides of bowl and feels soft and slightly sticky.
Lightly oil large mixing bowl and transfer dough from stand mixer bowl to oiled bowl. Cover with kitchen towel or plastic wrap.
Place in warm spot and let rise 1 hour until dough is puffier and leaves indentation when poked.
Now, make the cinnamon filling. Combine 1 packed cup brown sugar, 3 tablespoons ground cinnamon, and 6 tablespoons softened unsalted butter in medium bowl. Mix with fork until well combined and spreadable.
Preheat oven to 350°F. Lightly coat 9×13-inch baking dish with softened butter or cooking spray.
Cut parchment paper to 12×18 inches and lay on counter. Scrape dough onto parchment and press to 12×16 inches rectangle.
Evenly spread cinnamon filling on dough rectangle, leaving ½ inch bare at one short end.
Use parchment sheet to tightly roll dough starting from short side with filling to edge. Continue rolling by folding parchment over to other side.
Cut rolled dough into 12 equal pieces using sharp knife or unflavored dental floss.
Place 12 rolls evenly spaced in prepared baking dish.
Bake 20 to 25 minutes until rolls are puffed and set in center but still soft to touch. Do not overbake.