Bring a large pot of salted water to a boil and cook the egg noodles according to package directions. Drain and set aside, reserving 1/4 cup of the pasta water.

Season the beef generously with salt and black pepper. In a large skillet preheated over high heat, melt 1 tablespoon of butter. Add the beef in a single layer and sear quickly until browned but not overcooked. Remove from the pan and set aside.

Reduce the heat to medium and add the remaining 2 tablespoons of butter. Add the onion and mushrooms and cook until soft and translucent, about 3–4 minutes. Season lightly with salt and pepper, stirring occasionally, and allow them to cook until golden and tender. This step builds a lot of flavor, so don’t rush it.

Sprinkle the flour over the vegetables and stir to coat. Cook for about 1 minute to remove the raw flour taste. Slowly pour in the wine, stirring constantly and scraping up any browned bits from the pan. Gradually add the beef broth and bring the mixture to a simmer.

Stir in the Dijon mustard, paprika, and sour cream until smooth and creamy.

Return the beef to the skillet along with half of the reserved pasta water. Cover and let the sauce simmer gently for 10 minutes.

Remove the lid, increase the heat slightly to medium, and simmer for another 10 minutes, stirring occasionally, until the sauce thickens and reduces.

For the pasta, place the pot back over medium heat. Add 1 tablespoon of butter and the garlic, cooking until fragrant, about 1–2 minutes. Add the cooked noodles back to the pot along with the remaining reserved pasta water and freshly cracked black pepper. Toss until heated through.

Serve the stroganoff over the garlic butter noodles and finish with chopped chives and an extra crack of black pepper on top.