In a glass bowl, combine all the ingredients for the mojo and stir together. Cover and refrigerate for up to 4 hours before using. Preheat the oven to 350 degrees. Place the calabaza cut side down on a baking sheet and bake for about 30 minutes. Meanwhile, in a large soup pot melt the butter over medium heat. Add the onions and cook for about 10 minutes, or until the onions are softened. Add the plantain and cook for 5 minutes more, then add the cumin, coriander, salt and pepper. Stir together for 3 minutes more. Add the chicken stock, increase the heat to high and bring to a boil. Cover the pot and reduce the heat to medium. Remove the calabaza from the oven and, when cool enough to handle, scoop out the flesh, break it into small pieces and add to the soup. Add the apple juice and simmer for 30 minutes more, until the plantain is tender. Pour the soup through a strainer into another large pan. Transfer the solid ingredients to a food processor and puree until smooth, scraping down the sides of the bowl as necessary. Add the puree to the liquid mixture, stir to combine, and heat through over medium heat. If you prefer a thicker consistency, remove the cover and simmer until slightly thickened. Serve in shallow heated bowls, with a teaspoon or 2 of the mojo swirled into the center.

Note: If fresh calabaza (West Indian pumpkin) is unavailable, substitute acorn or Hubbard squash