Season 2 ½ lb short ribs with a generous sprinkling of salt and pepper. Let sit for 30 minutes.

Heat 1 tablespoon oil in the pot of your instant pot. Add the short ribs and sear until browned on all sides, about 10 minutes. Remove the short ribs and set them aside.

Add another 1 tablespoon oil in the pot and saute the chopped onion until translucent and softened, about 4 minutes. Add back the short ribs along with 4 smashed cloves of garlic, ½ cup white wine, ½ cup apple cider, 1 ½ cup beef broth, 1 bay leaf, 2 sprigs rosemary, 1 tablespoon white balsamic vinegar, and 1 tablespoon brown sugar. Close the instant pot and set to pressure cook on high for 1 hour.

Meanwhile, make the lemon herb sauce. Combine ½ cup chopped parsley with the juice of ½ lemon, 1 teaspoon lemon zest, and ½ cup olive oil. Season with salt and pepper and let sit for at least 30 minutes.

Make the sour cream mashed potatoes. Cut the Yukon potatoes into chunks and place them in a large pot. Fill the pot with enough water to cover the potatoes and season the water with salt. Cover the pot and bring to a boil over high heat. Reduce the heat to medium and continue to simmer until the potatoes are fork-tender.

Heat 1 cup milk with ¼ cup butter and 1 teaspoon minced garlic in a medium pot over low heat.

Drain the potatoes and mash. Add the milk and butter mixture, mashing until the potatoes are smooth. Stir in ⅓ cup sour cream and season the potatoes with salt. Keep warm.

Release the pressure from the instant pot. Spoon the mashed potatoes onto two plates and place the short ribs on top, spooning the sauce on top. Drizzle on the lemon herb sauce and serve immediately.