Preheat oven to 392F/200C.

Peel the sweet potatoes and soak them in water for about 5 minutes and then boil until soft. (You can also cut them into pieces before soaking and boiling.)

Boil, steam, or microwave sweet potato until soft. (I used boiled sweet potatoes.)

Next, mash the potato in a food processor.

Add the melted butter, sugar, and salt while it is still hot. Then gradually add heavy cream or milk, blending well in between. Once you achieve smooth doughy consistency, don't add any more.

Transfer the mixture to a bowl. Cover it with plastic wrap to keep it from drying out and refrigerate for about 30 minutes. (You can easily handle the cake mixture when it is cold.)

Grease the foil-type liners with butter.

Place the potato filling into the liner using two spoons.

Use plastic wrap to shape the sweet potato with your hands.

Whisk together the egg yolk and water to make the egg wash.

Gently apply the egg wash on the top of each sweet potato cake with a brush.

Bake the sweet potato cakes for about 10 minutes in the preheated oven until lightly brown.

Brush freshly baked sweet potato cakes with honey.