In a mixing bowl, stir together tapioca flour and black cocoa powder until evenly combined.
You can skip the black cocoa or replace it with matcha, ube, or strawberry powder for a different flavor, though the color may turn out differently.
In a saucepan, heat water and dark brown sugar until it just simmers. Remove from heat.
Stir 1 tbsp of the flour mixture into the hot syrup until smooth.
Return to low heat and stir continuously until it thickens into a sticky paste. Remove from heat.
This paste acts like a binder or "starter," which makes it easier to integrate the remaining dry flour without clumping. If you dump in all the flour at once, it can instantly seize and form dry chunks that won’t hydrate properly.
Add the remaining flour mix and stir to form a shaggy dough.
Knead on a tapioca-floured surface until smooth and pliable. If the dough is dry, add a few drops of water.
Cut off a small piece of dough, and cover unused dough with a damp cloth to keep moist.
Roll the piece into a rope of pencil thickness, cut into small chunks, and roll into pea-sized balls.
Roll a bit smaller than a boba, as the pearls will expand when they cook.
Place formed pearls in a bowl with a light dusting of tapioca flour to prevent sticking.
Bring a pot of water to a boil using a ratio of 8 cups water to 1 cup pearls.
Add the pearls, reduce to a simmer, and cook for 25 minutes, stirring occasionally.
Turn off heat and let sit, covered, for 15 minutes more.
Drain the pearls and rinse with cold water. Transfer the pearls to a bowl and stir in ¼ cup of maple syrup. Cool completely.
This section is inspired by https://runamokmaple.com/recipe/maple-boba
Spoon the pearls into a glass. Add ice. Fill the glass 2/3 full with black tea, then top with milk. Stir to mix. Add more maple syrup to taste, if desired.