Make the dough: Melt 2 tablespoons of butter in a small bowl and set aside. Bring the remaining 3 tablespoons of butter needed for the filling and glaze out of the fridge to soften.
Heat the milk to approximately 110°F-115°F. Mix together the warm milk and sugar in a small bowl. Sprinkle the yeast overtop. Let sit five minutes, then whisk the mixture together. Let sit another five minutes.
In a large bowl or the bowl of a stand mixer fitted with the hook attachment, mix 1 1/2 cups of flour with the salt.
Add the melted butter to the yeast mixture, then pour into the flour mixture. Mix until combined. Add more flour, as necessary, until you have a soft but workable dough.
Knead the dough for 5-7 minutes.
Prepare for your first rise by greasing the pressure cooker with 1 teaspoon of vegetable oil. Roll the dough into a ball and place into the pressure cooker. Turn the dough around so that it is lightly coated in oil. Place a glass lid or a glass plate overtop of the pressure cooker. Turn the pressure cooker to yogurt mode on low heat and allow to rise for 30 minutes (you will not have the option to set the timer to 30 minutes so be sure to pay attention or set one yourself).
After 30 minutes, remove the dough from the pressure cooker and place on a lightly floured surface. Roll it out to be a rectangle that is approximately 8"x10".
Prepare a 7" round pan by greasing it with nonstick spray or softened vegan butter.
In a small bowl, mix together the brown sugar and cinnamon for the filling.
Spread 2 tablespoons of softened butter along the middle of the dough, leaving at least 1/4" around the edges.
Sprinkle the cinnamon sugar mixture evenly over the butter. Gently press it into the butter.
Starting at a long end, carefully roll the dough into a tight swirl. Cut into 8 even pieces. Place the pieces evenly into the pan, placing one in the center and the remaining seven around the edges.
Cover with a clean towel and set aside for 20-30 minutes, allowing them to approximately double in size.
Once the rolls have risen, place a paper towel on top of the pan followed by a large piece of foil. Tightly wrap the foil around the pan with the paper towel inside of the foil.
Place 2 cups of water into the cooking pot of the pressure cooker and insert the rack. Place the wrapped pan in the pressure cooker on top of the rack. Put the lid on the pressure cooker and make sure the steam release is shut.
Turn the pressure cooker to Dessert mode on high for 25 minutes. It will heat first, then cook for 25 minutes. Once done, allow the steam to naturally release for 10 minutes (do not open the lid or manually release the steam - just leave as-is for 10 minutes) then open the steam release and then open the lid.
Using oven mitts, carefully remove the pan from the pressure cooker. Take the foil and paper towel off of the pan. Allow to cool slightly.
Meanwhile, make the glaze by combining 1 tablespoon of butter with the powdered sugar, vanilla, and 1 tablespoon of milk. Mix together until smooth and add more milk, as necessary, until the desired consistency is reached.
Spread the glaze over the slightly cooled cinnamon rolls. Serve warm!