Heat a large saucepan over medium heat and add the oil. When hot, add the garlic and onions and cook until beginning to soften, about 2 minutes. Add the potatoes, turmeric, coriander and pepper and cook for 2 minutes. Add the crushed tomatoes, beans, coconut milk, vegetable stock and nuts and bring to a simmer. Cook until the potatoes are tender and the liquid thickens, 20 to 30 minutes. Taste and season with salt if needed.
Serve the stew in bowls with lime wedges for squeezing. Garnish with cilantro and hot sauce if using.
For more ingredient substitution ideas, see the article below.