Pat the beef dry with a paper towel. Season the roast all over with salt and pepper. Sprinkle flour on both sides of the roast, and shake off any excess.
Turn on your instant pot to the sauté setting. Add the olive oil. Place the roast in the pot (it’ll be a tight fit—you might need to cut your roast into pieces and do it in batches), and allow it to sear, undisturbed, for about 6 minutes, or until a nice brown crust has formed. Use a meat fork to flip the meat and do the same on the other side. (While the meat’s searing, prepare the vegetables.)
Remove the roast from the pot, and add the tomato paste, balsamic vinegar, onions, celery, leeks, and garlic. Season with salt and pepper, and sauté the vegetables for about 5 minutes, stirring often, until softened.
Stir in the wine, and cook until it has reduced by half. Then add the beef stock, chicken base, sugar, Worcestershire sauce, bay leaf, and thyme. Add the beef back to the pot.
Seal the instant pot, and cook on manual high pressure for 40 minutes, followed by natural release for 10 minutes (‘natural release’ simply means not touching the pot or steam release valve for 10 minutes after the 40-minute program ends).
After 10 minutes, quick-release any remaining pressure by moving the valve to the venting position. After the pressure indicator drops down and it's safe to do so, open the instant pot, and stir in the carrots and potatoes. Close the lid, and cook on manual high pressure for another 5 minutes. Then natural release for 10 minutes before turning the valve to the venting position again. Serve!
Notes
Note 1: Nutrition information is for 1 serving of the recipe (1/8 of the original recipe, which serves 8), including beef, carrots, potatoes, and sauce. Note 2: If you want your sauce to have a more gravy-like consistency, remove all the vegetables and meat from the pot. Bring the sauce to a simmer with your Instant Pot on the sauté setting. Combine 2 tablespoons cornstarch with 3 tablespoons water, and drizzle it into the sauce. Simmer until the sauce has thickened to your liking (you can also add more slurry if necessary). Note 3: You can also cook this recipe in a Dutch oven. Here's how:
Complete all the "sauté setting" steps in your Dutch oven on the stove. Rather than 1/2 cup red wine and 1 cup stock, use 1 cup red wine and 2 cups stock. Also add 2 cups water.
Add the beef back to the pot, bring the mixture up to a boil, cover, and transfer to a 325°F/160°C oven for 2 hours.
After 2 hours, stir in the carrots and potatoes. Cover transfer back to the oven for 1 hour.