Whisk the ingredients for the sauce together in a small mixing bowl or glass measuring cup, and set aside.
Turn the Instant Pot on to SAUTE mode. Once HOT, add oil. Season short ribs generously with salt and freshly ground black pepper. Place 3-5 short ribs in the Instant Pot at a time, and brown all sides. Note, you will want to do two batches if you are doing more than 5 short ribs. Crowding will steam the meat, not brown it. Place the short ribs on a plate and set aside.
Add onion, carrot, and celery. Sauté for 3-5 minutes or until soft. Add garlic and sauté for an additional minute.
Pour in wine and chicken broth to deglaze the bottom of the pot. Scrape the bottom to remove any brown bits. Let simmer for 2 minutes, then return the short ribs to the pot. Pour in the sauce and add the bay leaf.
Place the lid on the Instant Pot and lock. Make sure the pressure valve is in the sealing position. Select MANUAL mode (high pressure) for 45 minutes. Let the pressure release naturally; this will take about 16-18 minutes.
Remove the lid and serve short ribs on a bed of homemade mashed potatoes.
Notes
To STORE Instant Pot short ribs, place them in an airtight container and refrigerate for up to 4 days. For longer storage, FREEZE the short ribs in a freezer-safe container for up to 3 months.To REHEAT, thaw in the fridge overnight if frozen, then warm in a saucepan over medium heat until hot, or use the microwave.