In your Instant Pot add your diced onion, olive oil and place on the sauté setting. Season with salt and pepper. Sauté your onion until it has gone nice and tender.
Peel and your carrots and potatoes and dice. Put to one side.
Dice your beef and remove any excess fat.
Add the beef to your Instant Pot along with your OXO cubes, salt and pepper and mix well. Allow your beef to brown a little. Season your pot with the thyme, rosemary and mixed herbs, throw in all your vegetables and mix well.
Add to the Instant Pot ½ litre of warm water.
Add the red wine and mix well.
Season one last time with salt and pepper.
Place the lid on your Instant Pot and cook for 45 minutes on the meat and stew setting.
While your beef stew is cooking make your dumplings. In a mixing bowl add the flour, butter, mustard and parsley. Mix well. Rub the fat into the flour until it resembles breadcrumbs. Add an egg and mix well with your hands. Add a little milk at a time until the mixture resembles a soft dough. Make into dumpling balls.
When the Instant Pot beeps manually move the valve, allow the steam out and remove the lid.
Stir your stew, add your dumplings to the top and cook for a further 15 minutes on the same setting.
Move the valve and allow the steam to leave the Instant Pot again and take the lid off.
Serve with warm crusty bread.