On a cookie sheet, toss the sliced onions with the oil, sugar, and spices. Roast the onions for 1 ½ hours, stirring occasionally, till deep golden brown. (You can also saute the onions on low heat for 30-45 minutes for the same effect.)
Meanwhile, make the dough. Combine yeast, sugar, and water in the bowl of a mixer and let it sit for a few minutes until the yeast starts to bubble. Add the salt, flour, and oil, and mix the dough till fully combined, and continue to knead for another 7-8 minutes. Transfer the dough to a greased bowl, cover, and let rise 1 hour.
In a large bowl, mix the ricotta, mozzarella, and caramelized onions. Add salt and pepper to taste and basil, if desired. Set aside.
Raise the oven temperature to 375 degrees Fahrenheit. Grease a 12-cup muffin tin.
On a floured surface, roll out the dough into a rectangle approximately 12x20 inches. Spread the cheese filling evenly over the dough and roll up the dough into a log. Slice the finished log into 12 slices and place one roll into each cup of the prepared muffin tin.
Bake the rolls for 20-25 minutes till golden brown and bubbling. Serve hot or warm.
Recipe by Overtime Cook at https://overtimecook.com/2018/05/07/saris-cheesy-onion-buns/