Bubble Tea Tart

In a food processor, add the flour, salt, and butter and pulse until the butter is broken up into small bits. Add the water and pulse until the mixture looks like crumbled dough.

Transfer to an unfloured work surface. Gather and shape into a flat disc.

Lightly dust the work surface with flour and roll out the dough into a 12-inch (30 cm) round.

Transfer to a 9-inch (23 cm) tart tin with a removable bottom. Roll a rolling pin over the dough to trim away the excess and create clean edges. Prick the dough all over with a fork. Refrigerate for at least 30 minutes and up to overnight.

Preheat the oven to 350°F (180°C). Set the tart tin on a sheet pan and line the pastry with foil so it covers the dough entirely. Fill with dried beans or pie weights.

Bake until the dough starts to look dry with a matte finish, 35 to 40 minutes.

Remove the foil and beans and continue to bake (on the sheet pan) until the pastry is light golden all over, 20 to 25 minutes.

Transfer the tart tin to a wire rack and let cool for 15 minutes. Reduce the oven temperature to 325°F (160°C).

In a medium bowl, beat the eggs with a whisk. Set beside the stovetop. Place a fine-mesh sieve over another medium bowl (you want this ready to go).

In a small saucepan, whisk together the heavy cream, milk, sugar, milk powder, and salt. Heat over medium heat until warm and steaming, about 3 minutes. Turn off the heat

Gradually whisk the warm milk mixture into the eggs. Pour the mixture back into the saucepan. Cook over low heat, whisking constantly, until slightly thickened (like a pourable custard sauce), about 7 minutes. You want to heat this very, very slowly. Once you start to feel the mixture thicken, it’s essentially done.

Immediately strain the mixture through the fine-mesh sieve (this will smooth it out). If the custard looks overly curdled (it happens), puree it in a food processor (or use an immersion blender) and strain once more. Whisk in the vanilla.

Transfer 1 tablespoon (15 g) of the custard to a pinch bowl and whisk in the molasses.

Pour the plain custard into the cooled crust. Using a spoon, drizzle the molasses custard on top of the plain custard in a stripey pattern (like you’re drawing a bunch of wide flattened S shapes down the custard). Drag a chopstick through the drizzle (following the same S shape pattern as before) to create a stripey, softly swirled design.

Bake the tart (on the sheet pan) until about 1 inch (2.5 cm) of the filling perimeter is set, but the center still jiggles, 25 to 30 minutes.

Transfer the tart tin to a wire rack and let cool completely. Refrigerate until chilled and set, at least 3 hours.

In a small saucepan, whisk together the brown sugar and water. Bring to a boil over high heat. Reduce to medium-low heat. Simmer, whisking occasionally, until slightly thickened, about 1 minute. Transfer to a medium heatproof bowl and let cool to room temperature (the syrup will thicken as it cools).

Meanwhile, prepare the boba according to the package directions. Cool the boba by rinsing with cold water and drain well. Stir the boba into the cooled brown sugar syrup.

If serving the whole tart (see Note), spoon the boba (draining off the excess syrup with a spoon) over the tart. This will carry some of the syrup to the tart but you don’t want to add too much or you’ll cover up the beautiful swirl design