Step 1: Mix the Dry Ingredients

1. In a medium bowl, whisk together flour, baking powder, baking soda, ground turmeric (if using), and kosher salt. Set aside.

Step 2: Infuse the Sugar

1. In a large mixing bowl, combine ¾ cup granulated sugar and lemon zest.
2. Rub the sugar and zest together with your fingers to release the lemon oils, enhancing the citrus flavor.

Step 3: Cream the Butter and Sugar

1. Add the softened butter to the lemon sugar mixture. Beat on medium speed using a stand mixer or hand mixer until light and fluffy (about 3–4 minutes).
2. Mix in the egg, egg yolk, lemon juice, and vanilla extract until fully combined.

Step 4: Combine Wet and Dry Ingredients

1. Gradually add the dry ingredients to the wet mixture on medium-low speed. Mix until just combined. Do not overmix.
2. Cover the dough with plastic wrap and refrigerate for at least 1 hour or overnight.

Step 5: Preheat the Oven and Prepare Coating

1. Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
2. Place powdered sugar in one bowl and the remaining ¼ cup granulated sugar in another bowl.

Step 6: Roll and Coat the Dough

1. Scoop about 1½ tablespoons of dough and roll it into a ball.
2. Roll each ball first in granulated sugar, then generously in powdered sugar, ensuring even coverage.
3. Place the coated dough balls on the prepared baking sheet, spaced 2 inches apart.

Step 7: Bake the Cookies

1. Bake in the preheated oven for 12–14 minutes, or until the tops are crackly and the edges are set.
2. Let the cookies cool on the baking sheet for 2 minutes, then transfer to a wire rack to cool completely.