If you prefer, ask your butcher to portion the fillet for you.
To speed things up, use 2 frying pans to cook the crepes.
To start, add the coriander seeds, mustard seeds, black peppercorns, salt and garlic cloves to a mortar and pestle. Smash the spices and garlic cloves together to form a rub.
Prepare the fillet by cutting off the tail end of the fillet so both ends have an equal thickness, then lightly coat with olive oil and generously rub the spices onto the meat.
Grill the fillet over a hot fire, searing it on all sides for about 2 minutes per side to evenly brown the meat. Once the meat is sealed, remove it from the fire and allow it to rest.
Cut the “lid” off of the loaf of bread by slicing a 2cm thick piece lengthways across the top of the loaf and hollow out the centre leaving a thick wall of bread at the base.
Generously butter the inside of the hollowed out loaf of bread, as well as the inside of the lid and place the fillet inside the bread. Close the wellington with the lid and double wrap the loaf in tinfoil.
Place the tinfoil parcel over the hot coals and braai for about 15 minutes for medium-rare, turning onto all sides to toast the bread.
Whilst the wellington is cooking, make the relish. Heat a splash of olive oil in a saucepan over a medium-high heat and fry the onions until they are soft and lightly golden.
Add the garlic, green chilli and smoked paprika and cook for an additional minute.
Stir in the tomatoes, tomato paste, sugar, season with salt and freshly ground black pepper and bring to the boil. Reduce the heat to low and gently simmer for about 15 minutes or until the sauce has thickened.
Remove the beef wellington from the braai and unwrap it from the tinfoil. If the bread isn’t toasty enough return it to the fire to bake over the open coals. Slice into thick rounds and serve with the spicy tomato and onion relish.