Heat a large pot or Dutch oven over medium heat. Add the olive oil, then the onions, and season with salt. Cook for 5 minutes, until beginning to soften. Add the carrot, and cook for another 5 minutes.

Add the celery and bell pepper, and continue to cook for another 5-7 minutes, until the vegetables are softened but not browning. Add the garlic, coriander, paprika, cumin, and oregano, and cook, stirring constantly, for another 1-2 minutes until very fragrant and the garlic begins to soften.

Add the black beans and stock, and simmer the soup over medium-low heat for 15 minutes.

Add the evaporated milk and stir. Remove half of the soup from the pot and blend until smooth with an immersion blender or regular blender with an open steam vent (not a cup blender), then return the pureed mixture to the pot.

Continue to simmer the soup over medium-low heat until thickens to your liking, another 20-30 minutes. Stir occasionally to prevent scorching on the bottom of the pot. Season with salt and pepper, to taste.

For the crostini: preheat the oven to 375° F. Slice the baguette into ½ inch thick slices, then rub the cut side of a garlic clove over the surface of the bread. Bake for 15-20 minutes, until lightly browned and crisp.

Serve the soup with the garlic crostini, an additional drizzle of extra virgin olive oil, and the optional cheese and avocado.