Tart Crust:

1. Prepare Dry Ingredients:
   • Sift the flour, powdered sugar, and a pinch of salt into a large mixing bowl.
2. Incorporate Butter:
   • Add the cold butter cubes to the dry mixture. Use a pastry cutter or two forks to cut the butter into the flour until the mixture resembles coarse cornmeal.
3. Add Wet Ingredients:
   • Add the egg yolks and vanilla extract. Mix with a silicone spatula until the dough just comes together. Be careful not to overmix the dough to keep it tender.
4. Chill the Dough:
   • Shape the dough into a disk, wrap in plastic wrap, and refrigerate for at least 1 hour.
5. Roll and Shape:
   • On a lightly floured surface, roll out the dough to about 1/8-inch thickness. Cut circles slightly larger than the tart tins and press the dough into the tins. Trim any excess dough from the edges.
6. Blind Bake the Crusts:
   • Preheat the oven to 350°F (175°C). Line the tart shells with parchment paper and fill with pie weights (or dry rice/beans). Bake for 10 minutes. Remove the weights and parchment, and bake for an additional 5 minutes, or until the crust is lightly golden. Let cool completely.

Blueberry Ganache:

1. Prepare the Blueberries:
   • In a small pot over medium heat, combine the blueberries and 2 tablespoons of water. Cook until the berries release their juice, about 5 minutes.
2. Strain the Mixture:
   • Pass the cooked blueberries through a mesh sieve to remove the skins and seeds, collecting the juice in a bowl.
3. Make the Ganache:
   • Heat the heavy cream in a small pot until just simmering. Remove from heat and pour over the white chocolate chips in a heatproof bowl. Let sit for 1 minute, then whisk until smooth.
4. Incorporate Blueberry Juice:
   • Stir the strained blueberry juice into the ganache until fully combined, creating a smooth, purple filling.

Assemble the Tarts:

1. Spoon the blueberry ganache into the cooled tart shells, smoothing the tops with a spatula.
2. Chill the tarts in the refrigerator for at least 1 hour, or until the ganache is set.