Drain the beans (if using canned) and save the liquid.
make the meat sauce:
Heat the oil in a skillet over medium heat, and add the diced onion. Cook it until tender and translucent, about 5 minutes.
Add the crumbled ground meat and the chopped garlic. Cook until the meat is browned and any liquid has evaporated.
Add the tomato paste and all the spices and seasonings. Cook for 3 to 4 minutes, until the tomato sauce caramelizes and sticks to the bottom of the pan in places.
Add the 1 cup of bean liquid or water and cook for 5-10 minutes on medium-low, until most of the liquid evaporates, but the mixture is still somewhat fluid. Turn the heat right down, cover the skillet, and keep the sauce warm.
make the yogurt sauce:
Stir together the yogurt, sour cream, dried mint, lemon juice, garlic, and salt. Set the sauce aside to allow the flavours to blend.
make the noodle soup base:
Measure the water, using any remaining bean liquid as part of the total, into a large soup pot and add the salt. Bring to a boil.
Break the spaghetti into 3 or 4 pieces. Add the broken spaghetti (or other pasta) to the boiling water, and cook them for about half the time recommended on the package directions. They will finish cooking as you add the other ingredients.
Add the drained beans and bring the water back to a simmer. Then pour in half of the yogurt sauce and half of the meat sauce. Stir well to incorporate the yogurt, then bring the soup back to a simmer, taste it, and add more salt or pepper if needed.
to serve:
Serve the remaining meat sauce and yogurt sauce in separate bowls on the side for people to add on top of their soup.
Serve additional dried mint to sprinkle over the soup in each bowl, plush chopped fresh cilantro and/or mint, if desired.
Notes
Leftover soup can be refrigerated for up to 5 days - stir the remaining meat sauce into the pot of soup before putting it into the fridge. Chill any remaining yogurt sauce separately to serve with the leftover soup. If the soup thickens when reheated, thin it with a little water.If using cooked beans, you can use the bean cooking liquid as for the canned bean liquid, or replace it with water.