01 - Preheat oven to 350°F (175°C). Line two baking trays with parchment paper.
02 - In a large bowl, whisk together the all-purpose flour, powdered sugar, cornstarch, and salt until evenly distributed.
03 - Add softened vegan butter, melted coconut oil, vanilla extract, and lemon zest to the dry mixture. Stir until a soft, cohesive dough forms.
04 - Scoop tablespoon-sized portions of dough and roll into smooth balls. Arrange on the prepared baking trays, spacing 2 inches apart.
05 - Gently flatten each dough ball with your fingers or a fork to create a uniform, even shape.
06 - Bake for 10–12 minutes until edges are lightly golden. Transfer to a wire rack and cool completely.
07 - Beat powdered sugar and softened vegan butter together until light and fluffy. Add lemon juice, lemon zest, and turmeric if using. Beat until smooth and creamy.
08 - Pipe or spread a small amount of filling onto the flat side of half the cookies. Top with remaining cookies, flat side down, to form sandwiches.
09 - Refrigerate assembled cookies for 30 minutes to set the filling and achieve the best texture before serving.