Heat oil in a large heavy-bottomed pot over medium-high
heat. Add onion and bell pepper, season with salt and pepper,
and cook, stirring often, until softened, about 6 minutes. Stir in
jalapeno and garlic and cook a further minute.
Add chili powder, cumin, paprika, and cayenne pepper
and cook, stirring constantly for 1 minute. Add tomatoes,
tomato sauce, and stevia, and bring to a boil. Reduce heat to
medium-low and cook at a simmer for 10 minutes.
Stir in all beans and allow to simmer until thickened and piping
hot, about 10 minutes. Serve immediately with a dollop of
yogurt and a sprinkling of chopped cilantro.