Brown Sugar Boba Milk Tea

1. For the syrup: Stir the brown sugar with 1 cup water in a small saucepan over medium-high heat. Bring to a simmer and cook until the mixture is the consistency of a loose maple syrup, about 8 minutes. Add the syrup to a heat-safe jar to cool while cooking the boba.
2. Place the boba in a fine sieve and shake off any excess cornstarch.  
3. Bring 6 cups water to a boil in a medium saucepan over high heat. Add the boba, stirring to prevent them from sticking together, then reduce the heat to medium and simmer until the boba float to the top and darken in color with translucent edges, about 4 minutes if the boba are fresh and about 7 minutes if they are frozen. Drain the boba and rinse with cold water (they will be chewy but will firm up as they cool).  
4. Add the boba to the brown sugar syrup and let sit until the syrup is at room temperature, about 20 minutes. 
5. For the tea: Divide the boba among 4 glasses using a slotted spoon and add 1 tablespoon of the syrup to each glass, letting the syrup streak and coat the inside of the glass. Divide the tea and milk evenly among the glasses and serve. 

Homemade Brown Sugar Boba:

1. Whisk 1/3 cup water with 1 cup of the tapioca starch in a small bowl. The slurry may look separated but will come together in the next step.
2. Add the brown sugar and 2/3 cup water to a small saucepan over high heat and bring to a boil, stirring to dissolve the sugar. Reduce the heat to medium high and whisk in the tapioca slurry until the mixture begins to just tighten and the water fully incorporates, about 30 seconds.  
3. Remove from the heat and stir in the remaining 1 cup tapioca starch using a heatproof spatula until it forms a ball of shaggy dough, 1 to 2 minutes.  
4. Dust a work surface with tapioca flour. Gather the dough together from the saucepan, transfer it to the surface and let cool, 3 to 4 minutes. Knead the dough until it is smooth, springy to the touch and no longer sticky, adding tapioca starch as needed, about 7 minutes. If the dough feels too dry, wet your hands and knead in water from your hands.  
5. Divide the dough into 6 pieces and cover with a damp kitchen towel. Roll out 1 piece of dough to a thickness of about 1/4 inch with a rolling pin. Use a 1/2-inch-wide bubble tea straw with the tip dusted in tapioca starch to cut pieces from the dough, making sure to dust the straw occasionally to prevent sticking. Gather the dough scraps into a ball and repeat the process. Discard any leftover dough after this step as it will be too dry to use again. Repeat with the remaining 5 pieces of dough.  
6. Lightly dust a baking sheet with tapioca starch. Roll the boba pieces into pea-sized balls and place on the prepared baking sheet. If the dough feels too dry or is cracking, dampen your fingers with a little water and knead it. Use immediately or freeze the boba in a single layer until hard, about 2 hours. Transfer to a resealable freezer bag and freeze until ready to use.