Heat the oil in a pan over a gentle heat, add the vegetables and garlic, and cook until the vegetables are just starting to turn golden. Pour the Guinness over, then add the bay leaf, parsley, oregano and stock cube. Simmer until the liquid has reduced by half.

Meanwhile, slice the beef into small rounds, slanting your knife against the meat. Brush each piece on both sides with a little oil. Put on a plate and set aside, or cover and return to the fridge until ready to use.

Melt the butter in a separate pan, add the flour and stir over a low heat until the mixture turns light brown. When the stock liquid has reduced, remove the bay leaf and pour into the butter and flour, stirring all the time until all the liquid is combined. Remove from the heat and, using a hand blender, puree the gravy until smooth. Return to the heat, add the sugar, then season with salt and pepper. If the gravy is too thick, thin it down with a little water. Add the olives and return to simmering point.

Heat a heavy-based frying pan until nearly smoking. Add the medallions of beef and cook for 1 minute on each side (or longer, according to how you like your meat cooked). Place on warmed plates and pour the Guinness and black olive gravy over. Garnish with oregano and serve with Colcannon (mashed potatoes with sauteed spring onions) or with plain mashed potatoes and fresh vegetables of your choice.