Step 1: Cook the Noodles
Bring a large pot of salted water to a boil. Add the egg noodles and cook according to package directions until al dente. Drain the noodles well and set them aside. You can toss them with a teaspoon of butter to prevent sticking.

Step 2: Brown the Beef and Vegetables
While the noodles are cooking, heat the olive oil in a large, deep skillet or Dutch oven over medium-high heat. Add the ground beef and cook, breaking it apart with a spoon, until it is mostly browned. Add the chopped onion and sliced mushrooms to the skillet. Continue to cook, stirring frequently, for 7-10 minutes, until the beef is fully cooked, the onions are soft, and the mushrooms have released their liquid and started to brown. Add the minced garlic, salt, and pepper, and cook for one more minute until fragrant. Do not drain the fat unless there is an excessive amount; a little fat adds a lot of flavor.

Step 3: Create the Sauce Base
Sprinkle the all-purpose flour over the beef and mushroom mixture. Stir continuously for 1-2 minutes until the flour is fully incorporated and has had a chance to cook slightly. This step is crucial for thickening the sauce and getting rid of any raw flour taste.

Step 4: Simmer the Sauce
Slowly pour in the beef broth while stirring or whisking constantly to prevent lumps from forming. Use your spoon or whisk to scrape up any browned bits from the bottom of the pan—this is where a ton of flavor is! Stir in the Worcestershire sauce and Dijon mustard. Bring the mixture to a gentle simmer.

Step 5: Thicken and Finish
Reduce the heat to low and let the sauce simmer for 5-7 minutes, stirring occasionally, until it has thickened to your desired consistency.

Step 6: Temper and Add the Sour Cream
This is the most important step for a creamy, non-curdled sauce. Turn the heat off under the skillet. In a separate small bowl, place your room-temperature sour cream. Ladle about ½ cup of the hot sauce from the skillet into the sour cream and whisk vigorously until smooth. This process, called tempering, gently raises the temperature of the sour cream so it doesn’t get shocked and curdle when added to the hot pan. Pour the tempered sour cream mixture back into the skillet and stir gently until the sauce is uniform, creamy, and luscious.

Step 7: Serve Immediately
Serve the hot Ground Beef Stroganoff immediately over the prepared egg noodles. Garnish generously with fresh chopped parsley or dill for a pop of color and fresh flavor.