Combine onion, carrot, fennel, cinnamon, garlic, bay leaves, run, wine, citrus zest and beef in a bowel, Cover and marinate in the fridge for at least 4 hours - ideally overnight.

Preheat oven to 160°c. Strain beef mixture, reserving marinade, beef and vegetable mixture separately. Bring marinade to the boil in a medium saucepan over medium-high heat. Simmer for 5-6 minutes, skimming impurities from the surface. Strain through a fine sieve.

Heat half oil and half butter in a large heavy-based flameproof casserole over high heat. In batches, sear beef, stirring and tossing frequently, for 5-6 minutes until browned, set aside. Add remaining oil and butter with eschalots, bacon and mushrooms and cook, stirring frequently, for 5-6 mins until vegetables have softened. Add reserved vegetables and cook, stirring for 4-5 mins until veg begins to soften.

Add tomato paste and stir for 1 minute, then stir in flour.

Return meat to the pan with marinade and stock, scraping bottom of pan with wooden spoon. Bring to the boil, cover and braise in oven for 2 to 2½ hours or until meat is tender.

Skim fat from surface of beef pan. Strain, returning liquid to pan and set aside beef and vegetables in a bowl. Return pan to medium-high heat for 3-4 minutes to reduce and thicken sauce. Return beef to the sauce with tarragon and return to a simmer.

Serve with mashed potato.