Combine 25 grams of water and 20 grams of black sugar* into a small sauce pan over medium heat. Add ⅓ of the tapioca flour and mix until the flour has dissolved and no lumps remain. Continue to constantly stir the content until the entire mixture thickens and turns dark brown and sticky. Remove from heat. DO NOT overcook.*The tapioca mixture needs to be stirred constantly. When you start to see tiny lumps on the bottom of the saucepan, you want to start stirring vigorously and make sure to not burn the starch at the bottom. The dough mixture should look dark brown, gloopy, but smooth when it is cooked properly.
Transfer the cooked tapioca dough to the remaining tapioca flour. Knead the tapioca flour into the dough while it's hot. Once all of the tapioca flour has been incorporated into the dough, the dough should feel velvety smooth and turn a light tan color.
Make bobas using a wire cooling rack:Flatten the tapioca dough and evenly roll it out to ¼ inch thick. Using a wire rack that has 1cm x 1cm spacing, press it as far into the dough as possible. Flip the rack, with the dough still on it, and roll over the dough a rolling pin to push it through the holes. If the dough is still stuck onto the rack, run your fingers over each row to push it through. Cover the pieces with a lightly dampened towel as you work.Roll each piece of "cubes" into pearls* or just to round off the edges. Dust the finished pearls with more tapioca flour if needed.Make bobas by hand:Roll the dough into a thin rope (also known as snakes) no larger than a ¼ inch thick. Cut the rope into ¼ inch pieces, then roll each pieces into pearls*. Cover them with a lightly dampened towel as you work, and dust the pearls with tapioca flour if needed.*Your tapioca pearls for both methods do not have to be perfectly round. As long they are relatively circular, it's good.*
In a pot of boiling water, add the pearls and give it a stir. Boil the pearls for about 20-25 minutes until the pearls are translucent on the outside and the entire boba is soft. The cook time can vary depending on the size of your pearls, so if the center of the pearls are still hard, cook them a little longer.Once cooked, strain the boba pearls and run them under cold water to remove excess starch.
In a small saucepan over medium high heat, combine the ¼ cup of black sugar* and ¼ cup of water. Stir until the sugar dissolves and starts to bubble.Add the boiled pearls to the black sugar syrup and cook the mixture for about 3-5 minutes until the pearls are dark brown and and the syrup is thick. Let the pearls cool completely.
For the brown sugar syrup:
Combine the black sugar and water into a small saucepan over medium high heat. Stir until the sugar dissolves and comes to a boil. Lower the heat and stir in the cornstarch slurry. Thoroughly stir the slurry into the black sugar syrup and bring it up to a simmer to thicken the syrup.Once thickened, transfer the syrup onto a plate or bowl and let it cool completely in the fridge until needed.
For the ice cream base:
Whisk together the coconut cream (or heavy cream) and sugar until dissolved. Pour the base into a prepared ice cream churner and churn the base until soft serve consistency. Fold the cooled tapioca pearls into the churned ice cream.*For an alternative method to make the ice cream, refer to the post.*
To assemble the ice cream bar:
Lace the ice cream mold with some cooled black sugar syrup. Then, fill the mold half way with the ice cream base and lace it again with a little more syrup. Insert a popsicle stick half way into the mold, and top off the mold with more ice cream base. Smooth off the ice cream bar with an offset spatula, then drizzle on a final layer of black sugar syrup. Repeat with remaining ice cream molds and freeze the ice cream for at least 3 hours or overnight. Make sure to cover the ice cream bars with either plastic wrap or parchment paper to prevent the ice cream from developing freezer flavor. Also, make sure the plastic or parchment touches the ice cream to prevent unwanted ice pockets.*Try to work as fast as possible and keep everything chilled so that the ice cream base can stay creamy.*
Remove the ice cream bars from the silicone mold and let the bars temper for a couple minutes. Enjoy!
*If Taiwanese black sugar is unavailable near you, you can substitute it for equal parts regular brown sugar with the addition of some unsulphured molasses.* We don't recommend using store bought tapioca pearls for this recipe, but we do understand the convenience it provides. If you decide to use premade pearls, make sure to to cook the pearls thoroughly or even overcook them. *Read more in post*