Preheat oven to 350
Wash and pat dry the stew beef, cut into bite-size pieces, and salt and pepper to taste.
Heat a dutch oven, or a large ovenproof pot with a lid. Add ½ Tbs butter to the hot pot, as soon as it melts, brown half of the beef. Be careful to not crowd the beef or it will not get that nice color. Remove browned beef to a separate plate, add ½ Tbs butter to the pot and brown remaining beef and then remove to the plate. Note: if your pot is smaller, you may need to brown in three batches.
Add ½ Tbs butter to pot along with onions and mushrooms. Sauté mushrooms until they start to lose most of their liquid, (about 5 minutes). Add minced garlic to the pot, sauté until it becomes fragrant, be careful not to burn it.
Add beef broth, red wine, worcestershire , tomato paste, mustard, salt, pepper, paprika, and dill to the pot, and stir to incorporate. Return the browned beef to the pot and stir. Turn heat to high, and bring mixture to a boil.
Once mixture boils, turn off the burner, cover pot, and transfer to the oven. Cook in the oven for 1 and ½ hours.
Remove pot to the stovetop, simmer uncovered for 20 minutes, to reduce liquid. Add heavy cream and chives, and simmer for another 15 minutes, stirring frequently. Serve over wide zoodles, (zucchini noodles) or cauliflower-mashed potatoes, garnish with parsley.
For the wide zoodles:
Place spiral sliced zucchini and or yellow summer squash in a microwavable bowl, salt and pepper to taste, cover the bowl with a plate and microwave on high for 3 minutes. Strain in a colander, and serve topped with the stroganoff. The heat of the stroganoff, will do the rest of the cooking for you.