1. Prepare a workspace by sprinkling powdered sugar over a marble slab, wooden cutting board, or large baking sheet. Fill your sink or a large bowl with cold water.

2. Place the sugar and 2/3 cup water in a large heavy saucepan and heat gently, stirring, until the sugar dissolves.

3. Add the cream of tartar and turn up the heat. Bring to a boil and cover, boiling, for 3 minutes.

4. Uncover and boil until the temperature reaches soft-ball stage, 240 degrees on a candy thermometer.

5. Place the bottom of the saucepan in the cold water you’ve prepared, stirring the sugar mixture constantly until it becomes thick and creamy.

6. Stir in the ground almonds and the egg whites, the place back over low heat and stir for 2 minutes more until the mixture is thick.

7. Spoon the marzipan onto your prepared work surface, and turn it with a metal spatula until it cools down enough to touch.

8. Coat your hands in powdered sugar and begin to knead the marzipan, working it until it is smooth and pliant.

9. Your marzipan can now be used immediately or stored by wrapping it in plastic wrap and keeping