Heat up stock in a small saucepan until it is hot to the touch. Set aside

Heat the oil in another heavy saucepan over medium heat and add the onion and the minced jalapeno. Cook, stirring until just tender, about 3 minutes. Add the garlic and rice and cook until the rice is coated with the oil. Add half the stock, stir and cover.  Reduce heat to low and cook for 5 minutes.  Most of the liquid will be gone.

While rice mixture is cooking, combine remaining half of stock with the spinach and cilantro leaves in a blender and blend at high speed until smooth. Add to rice mixture and cook until the liquid is absorbed and the rice is tender, about 15 minutes in all.  Remove from the heat and let sit, covered for 10 minutes or until ready to serve. Before serving, fluff rice with a fork, taste and season with salt if needed.