Pat the beef dry with paper towels and slice thinly across the grain into bite-size strips.

Pro tip: slicing across the grain shortens the muscle fibers and keeps each bite tender.

Dice the onion, slice the mushrooms, and mince the garlic. Measure out the broth, sour cream, and seasonings so everything’s within reach.

If you’re using xanthan gum, have it ready in a little dish — a tiny pinch goes a long way.

Heat the skillet over medium-high heat and add the olive oil or butter. Let it get hot but not smoking.

Sprinkle the beef with salt and pepper (and a little paprika if you like). Add half the beef to the pan in a single layer — don’t overcrowd. Sear until deeply browned on one side, about 1½–2 minutes, then flip and brown the other side for another 1–2 minutes.

Remove the browned beef to a plate while you cook the rest, then return all beef to the plate.

Pro tip: overcrowding the pan causes steaming. Brown in batches so you get flavorful, caramelized edges.

Reduce heat to medium. Add the diced onion to the skillet and cook until translucent, about 3–4 minutes.

Add the sliced mushrooms and a pinch of salt. Sauté until the mushrooms release their liquid and turn golden-brown, about 5–7 minutes.

Stir in the minced garlic and cook for 30 seconds until fragrant — don’t let the garlic burn.

Pour in the beef broth and use your spoon or spatula to scrape up the browned bits stuck to the pan (those are flavor gold). Bring the broth to a gentle simmer.

Stir in Worcestershire sauce, Dijon mustard, and paprika. Let the mixture bubble gently for 2–3 minutes so the flavors meld.

Pro tip: scraping the fond (brown bits) into the broth is the shortcut to restaurant-style depth of flavor.

Return the seared beef (and any juices that collected on the plate) to the skillet. Stir to combine.

Simmer for 2–3 minutes — the beef just needs a short time in the sauce to finish cooking and soak up flavor. Avoid long simmering so the meat stays tender.

Remove the pan from direct heat and let it cool for 30–60 seconds. Stir a few tablespoons of the hot broth into the sour cream to warm it up (this is called tempering).

Slowly stir the tempered sour cream back into the skillet until fully incorporated. Return the pan to low heat and warm through gently for 1–2 minutes — do not boil once the sour cream is added or it may separate.

Pro tip: always temper the sour cream before adding and avoid boiling afterward to keep the sauce silky and smooth.

If you want a thicker sauce, sprinkle a very small pinch of xanthan gum over the sauce and whisk quickly to avoid clumps. It will thicken within 30–60 seconds.

Alternative: simmer a minute or two longer to reduce, if you prefer not to use xanthan gum.

Taste and adjust salt, pepper, or a splash more Worcestershire if it needs brightness.

Turn off the heat and let the stroganoff rest for 1–2 minutes — the sauce will settle and coat the beef beautifully.

Serve over cauliflower rice, zucchini noodles, or mashed cauliflower. Spoon extra sauce and mushrooms over each serving.

Final pro tip: finish with a sprinkle of fresh parsley or a few drops of lemon juice to lift the richness right before serving.