Gather all the ingredients.

In a small saucepan, boil 1¾ cups water for the dashi. Once boiling, add ½ cup katsuobushi (dried bonito flakes).

Stir and turn off the heat. Set aside for 15 minutes to steep. Then, strain out the katsuobushi with a fine-mesh sieve. Now you have Katsuo Dashi. Set it aside.

Scoop out the seeds and membrane from 1 lb kabocha squash. Microwave it for 2 minutes to soften the outer skin.

Carefully cut the kabocha into wedges, then 2-inch (5 cm) pieces. Place the kabocha pieces in a single layer, skin side down, in a large pot.

Add the dashi, 2 Tbsp sake, and 1 Tbsp sugar.

Swirl the pot to mix the seasonings so you don‘t break the kabocha pieces by stirring. Turn on the stove to medium high and bring it to a boil.

Add 2 tsp soy sauce and ⅛ tsp Diamond Crystal kosher salt.

Swirl the pot again to mix the seasonings. The cooking liquid should cover about three-quarters of the kabocha; add water if needed.

Bring to a boil, then reduce to a simmer on medium low. Place an otoshibuta (drop lid) directly on top and cook for 20–30 minutes, until the flesh shows fine cracks near the skin or a skewer pierces the flesh easily.

Remove from the heat. Cover with the pot lid and let sit for 30 minutes to help the kabocha soak up more flavor.

You can serve the simmered kabocha at room temperature or reheat it before serving. To garnish with ginger (optional), cut it into thin slices and then thin julienne strips. Soak in cold water for 1 minute to remove some of the spiciness.

Drain well and set aside. Sprinkle the ginger on top of the kabocha. Serve and enjoy!