Preheat the oven to 325°F (163°C) and line a baking sheet with parchment paper.

In a bowl, mix the flour and sugar. Add cold butter and use a pastry blender to cut it into the flour mixture until crumbly.

Add water to the mixture and stir until the dough comes together. Transfer the dough to a clean surface and knead a few times until smooth.

Divide the dough into thirds. Color one portion royal blue, one portion teal, and one portion violet and rose to create a purple color.

Place the differently colored dough portions next to each other and gently flatten with your hand, allowing them to stick together. Transfer the dough to the parchment-lined baking sheet.

Use a rolling pin to roll the dough to a thickness of 1/4 inch (0.6 cm). Sprinkle mermaid sprinkles over the dough and gently press them in.

Use a pizza cutter or pastry cutter to cut the dough into 1/2-inch (1.3 cm) squares. Then, cut each square into a triangle shape.

Spread the cookies apart on the baking sheet by lifting and separating them.

Bake for 12-14 minutes or until the bottoms just begin to brown. Remove from the oven and let them cool completely.

Before serving, spray the cooled cookies with edible gold glitter for a magical touch.