Our Favorite Guacamole Ingredients 1/4 cup finely minced onion 3 ripe Haas avocados 1 1/2 tablespoons fresh lime juice (or lemon juice) 1 large Plum or Roma tomato, deseeded and diced (1/2 cup) 1 tablespoon chopped cilantro leaves, optional 1/2 teaspoon ground cumin 1/2 teaspoon salt 1 to 2 teaspoons minced jalapeño or Serrano pepper, optional