01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - In a large bowl, combine gluten-free flour, almond flour, sugar, lemon zest, sea salt, baking powder, and baking soda.
03 - Add coconut oil and mix with a pastry cutter or fork until mixture resembles coarse crumbs.
04 - In a small bowl, whisk together plant-based milk, lemon juice, and vanilla extract.
05 - Add wet mixture to dry ingredients and stir until a soft dough forms.
06 - Roll dough into 24 small balls, about 1 tablespoon each. Place on prepared baking sheets and gently flatten to about 1/4-inch thickness.
07 - Bake for 10-12 minutes, until edges are just beginning to turn golden. Cool completely on wire racks.
08 - In a saucepan, whisk together lemon juice, zest, sugar, and cornstarch. Add coconut milk and optional turmeric.
09 - Cook over medium heat, whisking constantly, until mixture thickens and bubbles, about 4-6 minutes.
10 - Remove from heat. Stir in vegan butter or coconut oil and a pinch of salt until smooth. Let cool to room temperature; it will thicken further as it cools.
11 - Spoon or pipe about 1 tablespoon of lemon curd onto the flat side of half the cookies. Top with remaining cookies to form sandwiches. Chill for 10-15 minutes to set, if desired.