Heat the oil in a large frying pan and fry the onion and pepper to soften. Add the minced beef and Garlic Granules and fry until browned. Stir in the tomatoes, kidney beans, tomato purée, Spices, Oregano and salt. Simmer uncovered for 20-30 minutes, stirring occasionally.
To serve, heat the taco shells in a warm oven for 2-3 minutes. Divide the chilli beef mixture between the shells, garnishing with shredded lettuce, soured cream and grated Cheddar cheese.