Heat a frying pan until hot. Add in half a tablespoon of olive oil and heat through. Add in the beef and sear on both sides.
Heat the remaining olive oil in a casserole dish. Add in the shallots, red onion, tomato purÃ©e and garlic and fry, stirring often, until lightly browned.
Add in the beef fillet, stout, stock and thyme. Season with salt and freshly ground black pepper.
Bring to the boil, reduce the heat and simmer for 20 minutes.
Remove the beef fillet and set aside to rest, keeping warm.
Bring the stout mixture to the boil. Rub the butter and flour together until combined and add to the sauce, a little at a time, stirring until absorbed, to thicken the sauce.
Make the mash by combining the chives and parmesan to taste.
Serve the beef with the cheesy, chive mash and spoon around the Guinness and shallot gravy.