In a cup, combine half of the warm milk with sugar and yeast and stir. Let sit for 5 minutes.
Place the flour in the Instant Pot. Add salt and mix. Add the yeast mixture and start mixing with a wooden spoon. Add the egg, melted butter, and the rest of the milk, little by little, to form a dough. Knead for a few seconds with a hand to make sure all ingredients are distributed evenly.
Make a ball and leave it in the Instant Pot. Cover with the glass lid (or with any lid you have but not the one that seals). Select the Yogurt button and set 60 minutes. Make sure it is not on the “Boil” program!
Line a 7-inch spring-form pan with a circle of parchment paper and grease the sides very well. Wrap the bottom of the pan with aluminum foil.
After 1 hour, the dough should have doubled its size. Extend it between two sheets of parchment paper. Using a rolling pin, make a rectangular about 1/2 inch thick.
Spread the prepared filling on top of the dough. Roll it from the shorter side to make a large log.
Cut the log into 6-7 rolls, almost as high as the pan you would be using.
Arrange the rolls into the pan. Cover them first with a baking sheet and then with aluminum foil.
Pour 1/2 cup water into the Instant Pot. Place the trivet so that the handles are on top
Insert the pan with the rolls in the Instant Pot on the trivet.
Close the Instant Pot and make sure the valve is set to “Seal.” Select “Manual” and set 30 minutes at high pressure.
When the program is over, let the pressure release naturally for 15 minutes. Release any remaining pressure manually.
Take out the pan holding the trivet handles with kitchen mittens. Check for doneness: a toothpick inserted in the center of the rolls should come out without dough, just with filling. If the rolls are not ready, cook them for additional 10 minutes.
Serve the cinnamon rolls right away with sour cream frosting.