In a large frying pan, heat the canola oil over medium heat. Add the diced onion and sauté until translucent, about 4-5 minutes.
Incorporate the finely chopped garlic and continue to cook for another minute until aromatic.
Introduce the ground beef to the pan, using a wooden spoon to crumble it as it cooks. Allow it to brown for about 6-8 minutes, then drain any excess grease.
Add the sliced mushrooms to the mixture, cooking for an additional 5 minutes until they soften and release their juices.
Sprinkle the flour over the beef and mushrooms, stirring well to combine. Allow it to cook for 1-2 minutes to eliminate the raw flour flavor.
Slowly pour in the beef stock, soy sauce, and yellow mustard, stirring continuously. Increase the heat slightly and let the mixture simmer for about 5 minutes until it thickens.
Lower the heat and gently fold in the Greek yogurt, stirring until everything is well combined and warmed through. Season with salt and black pepper to taste.
While the sauce is simmering, prepare the fettuccine according to the package directions. Once cooked, drain and set aside.
Plate the fettuccine and generously ladle the savory beef stroganoff over the top. Finish with a sprinkle of chopped chives for a fresh touch.