Cook pasta as instructed on the packet, drain, and set aside.
While the pasta is cooking, heat olive oil in a saucepan on medium heat and add minced garlic. Saute until translucent, then add chopped onions and saute until soft and starting to turn brown.
Add cooked black beans, saute for a minute, then add half of the water (1/2 cup if you're using the original measurements of this recipe) and bring to the boil. Lower heat and simmer for about 5 minutes.
Now mush the black beans right there in the saucepan with a fork or a ricer to blend in with the water to create a thick sauce. You can leave some beans whole depending on your choice -- this is your creation.
Once some or all the beans are mooshed to satisfaction and the concoction is nice and thick, add the tomato paste and saute for a minute to remove its rawness. Then add the chopped tomatoes, remaining water, and sugar (to reduce the acidity of the tomatoes) and mix well.
Add salt and pepper to taste. I generally prefer to do this as you go along, adding small amounts of salt and pepper to each stage of sauteing.
Allow the sauce to bubble nicely and simmer for about 5-10 minutes or until it is satisfactorily thick.
Now it's time to throw in the sliced olives, swirl around, then add the fresh basil and thyme and mix gently. Let simmer for a minute, then add the cooked pasta and mix well, ensuring that all the pasta is well covered by the sauce.
Remove the saucepan from the hob and let it sit for a minute away from the heat. Now if you're using the sour cream or Greek yogurt, this is when you would add it in and mix gently. Do not add this while the saucepan is still on the flame/burner or it might curdle. Well, even if it does, it's not going to taste bad, it's just going to look a bit odd, but will still taste just as good -- honest.
That's it -- all done. Garnish with some fresh basil leaves if you've got some lying around and serve hot.