Mochi

1. Combine the glutinous rice flour, sugar, and cornstarch in a medium-sized microwave-safe bowl, and whisk to combine
2. Pour the black tea into the dry ingredients, and whisk until smooth
3. Cover the mochi mixture with cling wrap and microwave for 2 minutes on high
4. Uncover and stir
5. Then re-cover and microwave for another 2 minutes, the mochi dough should be semi-translucent
6. If the mochi is still slightly liquidy/milky re-cover it and microwave at 1-minute intervals until cooked through
7. Allow the mochi to cool enough to handle
8. Add the vegetable oil and using gloved or oiled hands knead until smooth

Brown Sugar Boba

1. Cook the boba according to the directions on the packet and drain
2. Return the boba to the pot and add the brown sugar
3. Cook on medium heat until the sugar has dissolved and thickened
4. Remove from the heat and cool

Milk Tea Cream

1. Combine instant milk tea powder and boiling water in a small bowl, and stir until dissolved
2. Allow the milk tea mixture to cool to room temperature
3. Combine the cream and sugar in a large bowl and whisk until medium peaks
4. Add the cooled milk tea mixture and whisk until completely combined, and at stiff peaks. 
5. Transfer the cream into a piping bag fitted with a large round piping tip

Assembly

1. Dust your work surface with cornstarch 
2. Transfer the mochi to the dusted work surface, dust it with more cornstarch, and roll it out until it to 4 mm/0.15 inches thick
3. Use a large cookie cutter to cut out 4 rounds of mochi (you may need to gather the excess dough and re-roll it to get the last round of mochi)
4. Place the round of mochi in a small bowl (This helps make the dough into a cup shape for easy filling and molding of the dough)
5. Add a teaspoon of boba, and a dollop of milk tea cream
6. Carefully bring the sides of the mochi together over the cream, making sure the cream doesn't touch the edges of the mochi dough as it will make it difficult to seal.
7. Pinch the edges together to form a perfect mochi ball
8. Dust the seam with more cornstarch and serve!