Set your Instant Pot to SAUTÉ mode and add the butter, letting it melt completely. Once melted, add the minced garlic and cook for about 30 seconds until fragrant, then add the sliced mushrooms. Sauté for 3-4 minutes, stirring occasionally, until the mushrooms begin to release their moisture and soften slightly. This step develops deep umami flavors that form the foundation of the stroganoff. Freshly minced garlic makes a real difference here—jarred garlic can turn bitter when sautéed, so I always take the extra minute to mince it fresh.

Sprinkle the flour over the mushroom mixture and stir constantly for about 1 minute to cook out the raw flour taste and create a light roux. This roux will help thicken the final sauce. Add the stew meat (cut into 1-inch chunks), beef broth, Worcestershire sauce, and smoked paprika, stirring well to combine and ensure the flour is fully incorporated. Season with a pinch of salt and black pepper to taste.

Close the Instant Pot lid and set it to high pressure for 15 minutes. The pressure will quickly tenderize the stew meat while the flavors meld together. Once the timer finishes, perform a quick release by carefully turning the pressure valve to vent. Let the steam escape completely before opening the lid.

Stir the egg pasta directly into the hot stroganoff mixture—no need to cook it separately! Return the lid to the Instant Pot and set it to high pressure for 3 minutes (the pasta will finish cooking in the residual heat and sauce). Perform another quick release when the timer sounds. The pasta will absorb the flavors and create a creamier texture as it cooks.

Stir in the full-fat sour cream, which adds richness and a slight tang that balances the savory beef and mushrooms beautifully. In a small bowl, whisk together the cornstarch and 1/4 cup beef broth until smooth with no lumps—this slurry will thicken the stroganoff without making it gummy. Set the Instant Pot to SAUTÉ mode and bring the mixture to a gentle simmer, then slowly stir in the cornstarch mixture while stirring constantly. Continue cooking for 1-2 minutes until the sauce thickens to your desired consistency. I like my stroganoff with a sauce that coats the back of a spoon, not too thick, which keeps everything tender and elegant.

Turn off the heat and give the stroganoff a final taste. Adjust seasoning with additional salt and black pepper as needed. Ladle into bowls and serve immediately while hot, garnished with fresh parsley if desired. The stroganoff is best enjoyed fresh, though leftovers reheat beautifully on the stovetop with a splash of beef broth to restore the sauce consistency.