Preheat your oven to 350°F (175°C) and prepare two baking sheets by lining them with parchment paper.

In a large mixing bowl, rub together the granulated sugar and lemon zest with your fingers to release the fragrant oils.

Add the room temperature butter and brown sugar to the bowl and mix on medium-high speed until light and fluffy, about 3-4 minutes.

Incorporate the egg yolk, vanilla, and lemon juice, mixing until well blended.

Gradually add in salt, baking powder, baking soda, and flour. Be careful not to overmix.

Gently fold in the chopped frozen raspberries, preserving their shape.

Scoop the dough into large balls, about three tablespoons each, and place five on each baking sheet. Lightly sprinkle with flaked salt.

Bake for 12-15 minutes or until the edges are lightly golden brown.

Let them cool on the pan for a few minutes before transferring to a wire rack to cool completely.