Cut the sweet potatoes that you'll use as a topping into 1.5 cm squares without peeling the skin off. Peel and then cut the remaining sweet potatoes into 1.5 cm squares. Put each amount separately in some water to soak.

Add the milk to the sweet potatoes set aside for the pound cake batter, wrap loosely with saran wrap, and microwave for 5 minutes.

Once the sweet potatoes are soft, mash with a potato masher, strain, and let cool.

Take the sweet potatoes set aside for topping and for going inside the cake, add sugar and milk, cover with saran wrap, then microwave for 4 minutes. Take off the saran wrap and then microwave for another 2 minutes. Remove and set aside the squares with skin on them.

With an electric mixer, beat the softened butter until creamy. Add sugar and then beat again until it turns somewhat white.

Add brandy 2 teaspoons at a time to the well-beaten eggs while mixing at high speed. Add up to 2/3 of the beaten eggs.

Add in the potatoes from step 5 (no skin).

While sifting, fold the ◇ powdered ingredients into the batter.

Pour the batter into the pan, make a shallow hole down the middle of the cake, and top with sweet potatoes (skin on) and sesame seeds.

Bake in an oven at 160 ~ 170°C for 40 minutes. While it is still warm, remove the paper, and cover with a towel to cool. Once it has cooled down, wrap and store.

When cut, the cake should look like this. In this picture, 100 g of sweet potatoes were used for the potato chunks.