
Preheat oven to 350 F. Line 2 baking sheets with parchment paper.
In a large mixing bowl mix together granulated sugar and lemon zest with fingers, allowing the zest to open up and become more fragrant.
Add butter and brown sugar and mix on medium-high speed for about 3-4 minutes, or until light and fluffy. Add egg yolk, vanilla and lemon juice and mix together.
Slowly mix in salt, baking powder, baking soda and flour being careful not to over mix.
Chop or break up frozen raspberries into little pieces and lightly fold into cookie dough.
Scoop the dough into large balls, place 5 cookie dough balls on your lined baking sheet, and sprinkle with flaked salt.
Bake the cookies for 12-15 minutes until they are lightly golden brown at the edges.