Prepare your steamer by bringing water to a boil.

Place the sliced taro in a steamer basket or on a plate. Steam for 15-20 minutes, or until a chopstick pierces through the slices effortlessly.

Crucial Tip: Once steamed, if there is any water pooled in the bowl or plate with the taro, carefully pour it out. Excess water will make your dough too wet and sticky.

Transfer the hot, steamed taro to a large mixing bowl. Immediately add the purple sweet potato powder.

Use a potato masher or a fork to mash the taro while it's still hot until it's as smooth as possible and the color is uniform.

Add the condensed milk (and optional sugar if using). Put on a pair of food-safe gloves if you have them (this prevents sticking and is highly recommended).

Knead and mix the warm taro mixture with your hands until it comes together into a smooth, slightly sticky dough that doesn't stick to the bowl. If it's too dry and crumbly, add a teaspoon of milk. If it's too wet and sticky, knead in a little cooked glutinous rice flour or cornstarch, one teaspoon at a time.

Peel the banana(s) and cut them into short, chunky pieces, roughly the size of your thumb tip. You'll need one piece per mooncake.

Divide your taro dough into equal portions, about 35g each. Roll each portion into a ball.

Take one dough ball and flatten it in the palm of your hand into a disc about 1/4-inch thick.

Place one piece of banana in the center of the disc.

Gently bring the edges of the taro dough up and around the banana, pinching to seal completely. Don't worry about it being perfect—just make sure the banana is fully enclosed. Roll it gently between your palms to smooth it into a ball.

Lightly dust your mooncake mold with cooked glutinous rice flour or cornstarch and tap out the excess. This step is option.

Place the sealed dough ball into the mold. Press down firmly and evenly on the plunger, then gently release and push the shaped mooncake out onto a plate or tray.

Repeat with the remaining dough and filling.

These can be eaten immediately at room temperature. They are soft, lightly sweet, and delicious.

For a firmer texture, you can refrigerate them for an hour before serving. They are especially refreshing cold on a warm day.

Store any leftovers in an airtight container in the refrigerator for up to 2 days.