Sauté Aromatics and Mushrooms: Heat the olive oil and butter in a large, deep frying pan or skillet over a medium-high heat. Once the butter is melted and foaming, add the chopped onion and cook for 4-5 minutes, until softened and translucent. Add the minced garlic and cook for another minute until fragrant.

Brown the Beef: Add the ground beef to the pan. Use a wooden spoon to break it up. Season generously with salt and pepper. Cook for 6-8 minutes, stirring occasionally, until the beef is thoroughly browned. Don't rush this step; getting a good colour on the beef is key to the flavour. Drain off any excess fat if necessary.

Cook the Mushrooms: Add the sliced mushrooms to the pan with the beef. Cook for 5-7 minutes, stirring, until they have released their moisture and started to brown. I find that cooking them with the beef allows them to absorb all those lovely meaty flavours.

Create the Sauce Base: Sprinkle the smoked paprika and plain flour over the beef and mushroom mixture. Stir well to combine and cook for about one minute. This step cooks out the raw flour taste and will help to thicken our sauce.

Simmer the Sauce: Gradually pour in the beef broth while stirring constantly to avoid lumps. Stir in the Dijon mustard and Worcestershire sauce. Bring the mixture to a gentle simmer, then reduce the heat to low. Let it simmer gently for 10 minutes, uncovered, allowing the sauce to thicken and the flavours to meld together.

Finish with Soured Cream: Remove the pan from the heat completely. Let it cool for a minute. Stir in the room-temperature soured cream until it's fully incorporated and the sauce is smooth and creamy. Do not return the pan to the heat, as this can cause the soured cream to split.

Garnish and Serve: Taste the stroganoff and adjust the seasoning with more salt and pepper if needed. Garnish with fresh chopped parsley and serve immediately over hot egg noodles, rice, or mashed potatoes.