Prepare your meat for seasoning: Place all of the meat in a large bowl, squeeze the juice from the lemon over the meat and pour the vinegar over the meat as well. Add enough water to cover the meat, give the bowl a stir and let the meat soak for 10-15 minutes. Drain and rinse the meat, make sure to drain all the water from the bowl.
Season the meat with paprika, crushed garlic, 1 tablespoon of salt, ½ teaspoon of pepper. Let marinate overnight in a covered bowl in the refrigerator.
Prior to searing the meat, remove it from the refrigerator. Drain and reserve any liquid from the bowl.
Sear the meat: heat 1-2 tablespoons of olive oil in a large cast iron or stainless steel skillet. Once the oil and skillet is very hot, sear the meat in batches, about 3 minutes on each side. Space your meat out so you don't crowd the pan, otherwise you won't get a good sear. Transfer the seared meat to a tray or plate.
Heat 1 tablespoon of olive oil in a 12 or 16 quart stockpot. Saute the diced onions over medium heat until soft. Add the quartered tomatoes, bay leaves and bouillon cubes and saute until the tomatoes are cooked down.
Add the goat meat, lamb and half a tablespoon of salt to the pot and mix everything together. Add about 16 cups of water, cover the pot and bring to a boil. Once the pot reaches a boil, lower the flame and let simmer for 1 and ½ to 2 hours. While the pot simmers, prepare the vegetables. Peel and cube the potato, Japanese yam (batata doce), and African yam (inhame), yuca (mandioca). Halve the acorn squash, remove the seeds, peel it and cut it into 1-inch cubes. Peel and slice the green bananas into rounds and set everything aside. You can cover the bananas and vegetables in water to prevent them from browning until you're ready to add them.
After 1 and ½ to 2 hours of simmering, taste 1 spoonful of broth (allow it to cool slightly so you don't burn your mouth) and adjust the amount of salt to your liking. Feel free to add another bouillon cube if you wish but be careful not to over-season.
Add the banana, squash and all of the root vegetables (including the potato) to the pot. Cover and let simmer for 30-40 minutes, or until the vegetables are tender. If you want the starch from the vegetables to break down more, let it simmer for a little while longer until you are satisfied with the texture of the broth. Please note that modje thickens once cooled and stored in the refrigerator overnight.
Turn the flame off and let the modje rest (covered) for 15-20 minutes before serving, this step helps the flavors settle.
Ladle the modje into bowls and garnish with chopped cilantro (optional) and a side of ralon (yellow grits) or a side of white rice.