Heat the cooking oil in a pot over medium heat. Add diced onions and saute until slightly golden. Add the garlic and saute for 1 minute. Increase heat to medium-high; add ground beef and saute until no longer pink, stirring occasionally.
Then add crushed tomatoes, cumin ground, curry powder, turmeric powder, water, salt and pepper. Cover the pot and simmer for 20 minutes over medium-low heat. Add chopped tomatoes, sliced carrots, sliced potatoes and lemon juice; cover the pot and simmer until vegetables are tender and stew is thickened.