01 - Preheat oven to 350°F. Lightly grease a 12-cup mini muffin tin or tartlet pan with coconut oil or cooking spray.
02 - Combine flour, sugar, and salt in a medium bowl. Cut in solid coconut oil using a pastry cutter or fork until mixture resembles coarse crumbs. Add cold water 1 tablespoon at a time, mixing until dough just comes together.
03 - Divide dough into 12 equal portions. Press each portion into the bottom and up the sides of each muffin cup to form mini tart shells. Prick bottoms with a fork to prevent air bubbles.
04 - Bake for 10-12 minutes until edges are lightly golden. Remove from oven and let cool completely in the pan before filling.
05 - Whisk together lemon juice, zest, coconut milk, sugar, cornstarch, turmeric, salt, and vanilla in a saucepan until cornstarch is fully dissolved and mixture is smooth.
06 - Place saucepan over medium heat and whisk constantly until mixture thickens and just begins to bubble, about 4-6 minutes. Remove from heat immediately when thickened.
07 - Spoon warm lemon filling evenly into cooled tart shells. Smooth tops with the back of a spoon or small spatula.
08 - Refrigerate tarts for at least 1 hour until filling is completely set and firm. For best results, chill 2-3 hours before serving.