Heat oil in a large saucepan. Add the onion, garlic, jalapeño, and sauté for 4 minutes. Stir in the seasonings and cook for 1 minute more. Stir in the water, stewed tomatoes, potatoes, and carrots, and bring to a simmer. Cook over medium-low heat for 20- minutes, stirring occasionally. Stir in the spinach and cook for about 15 minutes more over low heat, continuing to stir occasionally.

Let stand for for 5 to 10 mintes before serving. To thicken, mash some of the potatoes against the side of the pot with the stirring spoon.