In a large pot, add water, lentils, half of the garlic, and sliced white onions.
Cover it with a lid and let it simmer for 20- 22 minutes until the lentils become soft.
Now, take out the lentils and the garlic from the pot and keep the remaining liquid aside.
Season the lentils with salt and pepper.
Heat oil in a pan. Toss in the bacon lardons and cook them for about 5- 6 minutes until they become soft.
Add the chopped white onions to it and cook it for about 5- 6 minutes more.
Then, add in the garlic and allspice and cook it for a minute.
Also, add pineapple, plantain, and tomatoes to it.
Cook it for 15- 16 minutes. Add the cooked lentils and the leftover liquid to it. Then, put in cilantro stems, halved jalapeno, and bay leaf. Cook it until it becomes thick.
When the soup is cooked, take out the cilantro stems, jalapeno, and bay leaf from it.
Now, garnish with cilantro leaves and season it as per your taste. Your lentejas or lentil soup is ready to serve.