Bring 16 oz. (453 mL) of chicken broth to a simmer over MEDIUM heat for 6 minutes. While broth heats, dice 6 oz. (170 mL) red onion. Set aside. Grate 8 oz. (226 mL) fresh parmesan cheese. Set aside.
Set Instant Pot to SAUTÉ. Add 2 tbsp. unsalted butter to the pot and melt. Once butter is melted, add 8 oz. (226 mL) arborio rice and stir it into the butter. Spread it evenly on the bottom of the pot to allow the rice to toast for about 3 minutes, stirring occasionally. Once rice is toasted, turn off heat and quickly add 2 oz. (56 mL) dry white wine (or dry vermouth) to deglaze the pot, stirring rice quickly.
Add 6 oz. (170 mL) pumpkin purée and warm broth to the pot. Mix thoroughly. Place Instant Pot lid on top and lock it in place. Make sure the release valve is DIS-ENGAGED so the pressure will not release. Set Instant Pot to PRESSURE COOK for 5 minutes, and hit START.
While the pressure builds and your risotto cooks, add 1 tbsp. olive oil to a sauté pan and sauté diced red onion over MEDIUM-HIGH heat for 7-10 minutes. When onions are nicely brown, turn off heat and quickly add 1 tbsp. balsamic vinegar to the pan, stirring quickly. Allow onions to sit and caramelize for at least 30 seconds.
When risotto is ready, release the pressure valve and allow the pressure to fully release before opening. When ready, remove lid. Add caramelized onions, grated parmesan, 1 tsp. honey, ½ tsp. salt, ¼ tsp. nutmeg, pinch of cinnamon and a nice sprinkle of fresh ground pepper. Stir completely and serve.