Slit and peel the thin white membrane covering the kidney if it has not been removed by the butcher.
Slice the kidney through the middle lengthwise. Trim off the white centre and rinse the kidney well.
Rinse beef and cut both kidney and beef into bite-size chunks, set aside.
Chop onions finely and set aside.
Mix the flour with a little salt and dredge the beef with it, set aside.
Pour vegetable oil in a dry saucepan or deep frying pan and place over high heat.
When the oil is hot, add kidney and fry until browned, drain from oil and set aside.
Fry the beef until browned. You can fry in 2 batches adding more oil if needed, drain from the pan into the plate with the kidney.
Add the chopped onions to the pan and fry scrapping bits from the frying pan.
Reduce the heat to medium-high, stirring often until brown along the edges.
Add the fried kidney and beef, add seasoning cubes, water, thyme, stout, black pepper and chilli pepper. Stir well, cover and bring to a boil. Reduce heat to a very gentle simmer and cook for 1 hour. Stir, taste and add salt.
Cover and continue simmering for another 45 minutes until gravy is thick and beef is very tender, take off the heat and set aside to cool completely.