Heat oil in a heavy pot over medium heat. Add onions; sautee until light brown and tender, about 10 minutes. Add oregano and cumin; stir for 1 minute. Increase the heat to medium-high. Add turkey; stir until no longer pink. Stir in chili powder, bay leaves, cocoa powder, salt and cinnamon. Add the tomatoes with juice. Mix in broth and tomato sauce. Bring to a boil. Reduce heat and simmer for 45 minutes, stirring occasionally. Add the beans to the chili and simmer until the flavours blend, about 10 minutes. Discard the bay leaves. When ready to serve, garnish with red onion, cilantro and plain yogurt.