Ingredients   For the Sofrito 1 pound onions, roughly chopped 2 ribs celery, roughly chopped 1 bell pepper, roughly chopped   For the Masa (Dough) 1 pound harina de maiz (use pre-cooked variety such as Goya or P.A.N. brands) 6 cups water 2 teaspoons salt 3 corn on the cob ½ cup Olive Oil 1…