Preparation time: 25 mins (plus 30 mins to chill) Cooking time: 12 mins Serves: 4 2 cups cooked black beans 1 cup finely crushed tortilla chips(preferably blue corn chips) 1/2 cup salsa, plus extra for serving 1/2 cup grated Cheddar cheese 1 large egg, lightly beaten 1 scallion (white and green parts), trimmed and finely …