Step 1

Melt 1 tablespoon of the butter in a large, heavy-bottomed pot or Dutch oven over medium-high heat. Add the mushrooms, season with salt and pepper, and cook, stirring rarely, until browned, about 5 minutes. Transfer to a medium bowl and set aside.

Step 2

Reduce the heat to medium and add the remaining 2 tablespoons butter. When the butter has melted, add the onion and garlic, season with salt and pepper, and cook, stirring occasionally, until softened, 4 to 5 minutes. Add the beef, 3/4 teaspoon salt, and 1/4 teaspoon pepper. Cook, breaking the meat into smaller pieces with a wooden spoon and stirring occasionally, until just cooked through and no longer pink, 6 to 8 minutes.

Step 3

Sprinkle in the flour and paprika. Cook, stirring frequently, until the raw flavor has cooked off the flour, about 1 to 2 minutes. Add the broth and mustard and scrape up any browned bits from the bottom of the pot. Increase the heat to medium-high and bring to a simmer.

Step 4

Add the noodles and reserved mushrooms along with their accumulated juices and stir to combine. Reduce the heat to medium-low and simmer, stirring occasionally and making sure the noodles are always mostly submerged in liquid, until the noodles are just cooked through and tender, about 6 to 8 minutes.

Step 5

Remove from the heat and stir in the yogurt until completely incorporated. Taste and season with salt and pepper as needed. Sprinkle with the parsley if desired and serve immediately.