Doña Tomasa and other Oaxacans often thin their guacamole with water to make a dipping sauce. Sometimes a little cream or milk is added as well.

Ingredients

　　2 ripe California avocados (1 pound total), quartered, pitted, and peeled

　　1/2 cup chopped fresh cilantro

　　1/2 cup minced white onion

　　1 fresh serrano chile including seeds, minced

　　2 teaspoons fresh lime juice, or to taste

　　1 1/2 teaspoons kosher salt, or to taste

　　3/4 to 1 cup cold water

　　Mash together all ingredients in a bowl with a fork until smooth, using enough water for desired consistency. For a smoother dip, puréei n a blender.

　　Cooks' note:

　　Guacamole can be made 1 hour ahead and chilled, its surface covered with plastic wrap.