Step 1In the bowl of an electric mixer fitted with the paddle attachment, combine the almond paste and granulated sugar on medium speed until the mixture obtains the consistency of a fine meal, about 10 minutes, scraping down the sides and bottom of the bowl as needed. (Or pulse in a food processor, then place in the mixing bowl.) Add the powdered sugar and mix on low speed until well combined, about 5 minutes.
Step 2With the mixer still on low speed, add the egg whites about a teaspoon at a time, making sure each addition of egg whites is incorporated before adding any more. Stop and scrape down the sides and bottom of the bowl midway through mixing. If there are any lumps, stop adding the egg whites and continue mixing until the mixture is smooth. Resume adding the egg whites very, very slowly until they are completely incorporated, scraping down the sides and bottom of the bowl as needed.
Step 3Slowly add the cold water, 1 teaspoon at a time, until you have added 2 teaspoons, scraping down the sides and bottom of the bowl as needed. Stop adding water once the mixture looks shiny. You may not need to use all 3 teaspoons. Transfer the finished batter to an airtight container and refrigerate overnight.
Step 4Heat the oven to 350 degrees. Line a baking sheet with parchment paper. Fit a piping bag with a three-quarter-inch, No. 9, stainless-steel round tip and fill the bag with the macaroon batter. Pipe the batter into slightly rounded disks, about 1 1/4 to 1 1/2 inches in diameter, onto the baking sheet, 1 inch apart. Dab the center of each disc with a damp paper towel to flatten any peak.
Step 5Bake for 13 to 15 minutes or until set on the sides. The edges should be light brown and the surfaces lightly crinkled with small, fine cracks. Remove the baking sheet to a wire rack and let the macaroons cool completely on the baking sheet. Gently remove from the paper backing. You also can cut between the rows of cookies with scissors and store them with their paper backing. The macaroons can be kept in an airtight container at room temperature up to 5 days.