Sift 3/4 cup confectioners' sugar into a large bowl. Add almonds and superfine sugar; stir together. Make a hole in the middle and add sweetened condensed milk. Stir well until mixture is completely smooth. Add red food coloring. Divide dough in half and wrap both pieces in plastic wrap. Refrigerate for 15 to 20 minutes.
Sprinkle 1 tablespoon confectioners' sugar over a clean work surface. Roll dough out to the thickness of a pinky finger. Punch out hearts using a heart-shaped cookie cutter. Place cookies on a baking sheet covered with waxed paper to harden.