Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, combine granulated sugar and the zest of the lemon, rubbing together to release oils.

Cream together room temperature butter and brown sugar until light and fluffy.

Mix in egg yolk, vanilla extract, and lemon juice until smooth.

Sift in salt, baking powder, baking soda, and flour, mixing gently to combine.

Fold in chopped frozen raspberries gently with a spatula.

Scoop the dough in generous balls and place on the prepared baking sheets.

Lightly sprinkle flaked salt on top of each cookie ball.

Bake for 12-15 minutes until lightly golden around edges but soft in the center.

Let cool on the baking sheets for a few minutes before transferring to a wire rack.