Make the simple syrup by heating the water in a small pot on the stove until it's almost boiling. Turn off the heat and stir in the granulated sugar until it's dissolved. Let the mixture cool.
For each cocktail, place 3 frozen cherries in the bottom of a glass. Mash them with a fork. This is important for flavor and to give the cocktail its red color.
Add the Amaretto, soda pop, cooled simple syrup and lemon juice. Stir to combine.
Garnish each drink with an orange or lemon slice and an additional cherry, if desired. Serve immediately, ideally before they lose their fizz. Refrigerate leftovers for up to three days.
Simple syrup is made with equal parts sugar and water. It's a good idea to make more than enough for one drink. You can store it in the refrigerator in a sealed container for up to a week and use some as you need it.The drink will have fewer calories and sugar if you use sugar-free 7UP or Sprite.