Step 1

Gather all the ingredients.

Step 2

Peel the sweet potato’s skin alternately to create stripes. Then cut and discard both ends.

Step 3

Cut the sweet potato into ½-inch (1.3 cm) thick rounds. Soak them in water to remove starch for 5 minutes and then drain.

Step 4

In a medium saucepan, add 1 cup water, 2 Tbsp sugar, and juice from ½ lemon.

Step 5

Add the sweet potato rounds (ideally in a single layer) in the saucepan and place the Otoshibuta (drop lid) on top instead of the regular lid (here's why). Bring it to boil over medium heat.

Step 6

Once boiling, skim off the scum and foam with a fine mesh skimmer. Turn down the heat to simmer/low heat. Cook for 15-20 minutes.

Step 7

When it’s almost done, open the Otoshibuta and insert a bamboo skewer in the center of the thick sweet potato and see if it goes through.

Step 8

Turn off the heat when it’s done cooking, and serve. Ideally, set aside and let cool for 2 hours so sweet potatoes can absorb more flavors. You can chill the sweet potatoes in the refrigerator before serving, or serve at room temperature.

Step 9

You can keep the simmered sweet potatoes in the refrigerator for up to 5 days. You can freeze them but the texture of the sweet potatoes will be changed slightly.