Having a recipe for arroz caldo is like having a recipe for chicken soup - you won't need one once you know the basic steps. Its base is just chicken, water or broth, and rice (cooked or uncooked). The flavorings are ginger, scallions, and soy sauce or patis (you can also use garlic and saffron, but I don't). You can also add a squirt of lemon juice or calamansi, Asian sesame oil, hot sauce, and fried garlic as condiments.
When you make arroz caldo, it will start off soupy (as shown in the picture), but as it cooks and the rice absorbs more of the broth, it will become thicker and more like porridge. As long as the rice is tender, you can eat it at any stage that you like. If it's too thick for you, you can always add more chicken broth or water to loosen it up. You can also keep adding to this as you go. For example, if the pot is half gone and you know more people will want to eat it, just add more chicken, rice, and flavorings, and you can keep extending the soup.
Be sure to use a short- or medium-grained white rice and not Uncle Bens, North Carolina rice, or basmati rice. If you use an Asian rice (Japanese, Thai jasmine, Chinese, etc.), you're sure to have good results. These rices have more starch, which is what gives the arroz caldo its body. You can start off with uncooked rice, but I almost always used cooked rice, because I usually have some around.
To make the broth, I poach skinless, bone-in chicken breasts or thighs in chicken broth. Some brown the chicken and saute garlic and onions before adding the broth, but I don't because I like the clear flavor of unbrowned chicken in this case. The bones are important because they add flavor to the broth, and I like to use organic chicken broth instead of water for flavor. My dad uses water, but he will add a few chicken bouillon cubes to up the flavor, and he sautes the chicken with garlic and onion powder, but he doesn't have the heat so high as to brown the chicken. You can also use shredded rotisserie chicken and chicken broth if you don't have time to poach and shred the chicken.
The amount of ginger and soy sauce or salt is up to you. Let your tastebuds guide you. I like to grate the ginger with a microplane into the pot, so I know right away how gingery it will be, but others put "coins" of ginger and let them steep in the soup instead (if you do this, remove the coins before serving).
Below, I will give my "Italian grandmother" instructions, which is more technique than exact recipe, but if you'd like to see another recipe, click here to see a nice recipe I found on Nibbledish.
3 bone-in skinless chicken breasts or 4 bone-in skinless chicken thighs (or shredded rotisserie chicken if you're taking a shortcut)
2 containers Pacific organic chicken broth, a large can of chicken broth, water, or water with bouillon cubes
4 cups cooked rice or 2 cups uncooked short- or medium-grained rice
Ginger, peel enough to cut into 4-10 1/4 inch coins, depending on how much you like the taste of ginger; alternately you can grate in an amount to your liking
3 or 4 scallions, chopped finely, separating green and white parts
Soy sauce or patis
Fresh ground black pepper or white pepper
Table-side condiments (optional)
Soy sauce or patis
Lemon or calamansi wedges
Hot sauce or togarashi ichimi (Japanese red pepper)
Finely chopped scallions
Fried garlic (either can be homemade or can be bought at the Asian store)
Put chicken in a dutch oven pot and cover with chicken broth. If you're using canned chicken broth or chicken broth in the cardboard containers, and you don't have enough broth to cover the chicken, just add water until the chicken is covered. If you're using water and chicken bouillon cubes, cover the chicken with water and throw in a few cubes. It doesn't have to be exact and you can always add more bouillon cubes later if you want more chicken flavor. If you're using water, then just cover with water.
Add grated ginger, white part of scallions, pepper, and a couple splashes of soy sauce to the chicken and broth and bring to a low simmer (do not boil) and let poach until chicken is cooked, about 20-30 minutes. Add uncooked or cooked rice now (or you can add it after you cook the chicken and shred it). If the porridge is getting too thick, just add more water.
To check if the chicken is done, you can take two forks and pull the meat apart -- if it comes away easily and you don't see any pink, then it's cooked. If you poach it longer than 30 minutes, it doesn't matter either. You can't overcook the chicken in this recipe.
Once the chicken is done, take it out and shred it with two forks. Add the shredded chicken back into the pot. Taste and adjust seasonings, adding more soy sauce if it's bland, or adding more water if it's too salty.
When the rice is tender or when the soup has reached a consistency you like (soupy to very thick) and you're about ready to serve it, add 1/2 of the remaining green scallion and stir into the pot.
Serve the soup and let people top their own soup with the condiments of their choice (scallions, fried garlic, lemon or calamansi juice, soy sauce, sesame oil, fried garlic).
Leftover version with rotisserie chicken, chicken broth, and cooked rice:
For an even quicker meal, put some shredded rotisserie chicken, chicken broth, and cooked rice into a pot. Add ginger, soy sauce, and scallions. Simmer until the rice thickens the broth and it becomes like porridge. Serve with above condiments.