Preheat the oven to 325˚F. In a large dutch oven, heat olive oil over medium-high heat. Season the beef with ½ teaspoon salt and ½ teaspoon pepper. Once the oil is shimmering, add beef and sear for about 3 to 4 minutes per side. Remove with a slotted spoon and set aside.
Add mushrooms and onions to the dutch oven, and season with the remaining salt and pepper. Cook for 6 to 8 minutes, or until the mushrooms have released all their moisture and the onions are golden brown. Add apple cider vinegar to deglaze the pan and cook for about 1 minute.
Add flour, paprika and Dijon, stirring to coat the onions and mushrooms evenly in flour. Add the beef and beef stock and bring to a boil, then reduce heat to a simmer.
Transfer the dutch oven to the oven and cook for about 2 ½ hours, or until the beef is very very tender. Remove from heat and whisk in greek yogurt. Garnish with parsley, then serve over egg noodles.
Notes
*Nutrition label does not include egg noodles.To Store: Allow the stroganoff to cool completely before transferring it to an airtight container to store in the fridge or freezer for up to 3-4 days or up to 3 months in the freezer (without noodles)To reheat, add to a pot over medium-low heat until heated through or warm in the microwave with a vented cover to avoid splattering.Tip: Use sour cream instead of Greek yogurt.