Chop all sofrito items in a food processor or chopper.
Heat oil in a medium caldero or heavy pot on medium heat.
Stir in the sofrito (chopped onion, scallion, cilantro, bell pepper and garlic) and cook about 5 minutes, until soft.
Add the tomato and 1/4 teaspoon salt, cook another minute until soft.
Stir in rice and mix well.
Add the gandules, water, bouillon, sazon, and salt and taste liquid for flavor (the liquid should be salty enough to give it flavor).
Mix well. Add more salt as needed.
Reduce flame to medium-low and let water boil down until it is completely absorbed.
Once water barely skims the top, set flame to low and cover for 20 minutes without stirring or lifting the lid.
Remove from heat and let it sit 5 minutes. The steam will cook the rice.
Notes
If you want to add pork, you can add 1 pork chop seasoned with 1/4 teaspoon adobo seasoning or 1 smoked pork chop, diced small and saute before step one to brown. Then set aside and proceed adding the pork back in when you add the water.