Sauté the Aromatics: Heat the oil in a large pot over medium-high heat. Add the diced onions, minced garlic, and chopped cilantro. Sauté until fragrant, about 2-3 minutes.
Cook the Pigeon Peas: Add the ½ cup of water, sofrito, and pigeon peas. Stir well and let cook for 3-4 minutes to allow the flavors to meld. If using bell pepper, add it at this stage for extra depth of flavor.
Add Rice and Seasonings: Rinse the rice thoroughly and add it to the pot. Pour in the 3 cups of water, tomato sauce, oregano, Sazon, adobo, salt, chicken bouillon, and the optional bay leaf. Stir everything together to distribute the flavors evenly.
Cook the Rice: Bring the mixture to a boil over medium heat. Once boiling, cover the pot, reduce the heat to low, and let the rice cook until the liquid is absorbed and the rice is tender (about 20-25 minutes). Stir occasionally to prevent sticking.
Fluff and Serve: Remove from heat, discard the bay leaf (if used), and fluff the rice with a fork. Let it sit for a few minutes before serving. Enjoy your arroz con guandules dominicano with your favorite pollo and avocado slices!
Storage Tips: If you have leftovers, store them in an airtight container in the refrigerator for up to 4 days. Reheat with a splash of water to restore moisture.