- Pat the Osso Buco completely dry with a paper towel and season with salt and pepper. Sprinkle the Osso Buco with flour to coat evenly and shake off any excess. Set aside on a plate.
- On your instant pot, turn the Sauté function on high. Add oil and heat until the oil sizzles, about 1 minute. Sear the Osso Buco for about 5 minutes on each side until golden brown and transfer onto a plate.
- Add butter and melt over medium-high heat until it starts to bubble. Add onions, garlic, celery, carrots, and thyme. Sauté until tender, about 2 minutes.
- Stir in tomato paste and mix well. Pour in the wine, tomato sauce, and chicken broth, mix well.
- Return the Osso Buco to the pot and switch to pressure cooking mode on manual High and seal the lid. Let the Osso Buco pressure cook until tender, about 30 minutes.
- Once the time is up, you can let the instant pot slowly release the pressure or quick release the remaining pressure.
- Season with salt to taste and serve with rice, pasta, or potatoes
- Enjoy!