Vibrant Hibiscus and Ginger Tart with Buttery Shortbread

For the shortbread crust: In a large bowl, combine 1 1/2 cups all-purpose flour, 1/4 cup granulated sugar, and 1/4 teaspoon salt. Cut in 1/2 cup cold, cubed unsalted butter until the mixture resembles coarse crumbs. Add 1 large egg yolk and mix until a dough forms. Press the dough evenly into a 9-inch tart pan with a removable bottom. Chill for 30 minutes.

Bake the crust at 375°F/190°C for 15-20 minutes, or until lightly golden. Remove from oven and let cool slightly.

For the hibiscus-ginger filling: In a medium saucepan, combine 1/2 cup dried hibiscus flowers and 1 1/2 cups water. Bring to a simmer over medium heat and cook for 5 minutes. Strain the liquid into a clean saucepan, discarding the hibiscus flowers.

To the hibiscus liquid, add 1/2 cup granulated sugar and 2 tablespoons grated fresh ginger. Bring to a simmer over medium heat. In a small bowl, whisk 2 tablespoons cornstarch with 2 tablespoons cold water to create a slurry. Gradually whisk the cornstarch slurry into the simmering hibiscus mixture. Cook, stirring constantly, for 2-3 minutes until the filling thickens to a pudding-like consistency.

Pour the hot hibiscus-ginger filling into the pre-baked shortbread crust. Smooth the top with a spatula.

Chill the tart in the refrigerator for at least 3 hours, or until completely set. This allows the filling to firm up and the flavors to meld.