Wash the kabocha squash, remove the skin and seeds, and slice it into 1cm thick pieces.
Place the kabocha slices in a steamer and steam them for 15 minutes until cooked.
Transfer the steamed kabocha to a bowl and mash it with a fork.
Heat a pan, add butter, and lightly sauté the mashed kabocha.
Put the kabocha puree in a cup and place an egg on top.
Cook the egg in a hot water bath until set.
Season with salt and pepper, and garnish with bacon, parsley, or other toppings to finish.