Preheat the oven to 350 degrees F. Line baking sheet with parchment paper. Set aside.

Whisk together flour, baking powder, 1/2 teaspoon sea salt and lemon zest in a large bowl. Set aside.

In an electric standing mixer fitted with the paddle attachment, spread the butter around the bowl by mixing on low for about 20 seconds. Bump the speed up to medium low, and slowly stream in the granulated sugar. Cream the butter and sugar on medium speed for about 2 minutes.

Scrape down the bowl with a spatula then add the eggs one at a time, and mix on medium until incorporated. Add lemon or vanilla extract and beat until blended.

Turn off the mixer and add the flour mixture. Mix on low speed until the flour disappears.

Scoop heaping tablespoonfuls of dough into plates. Form each dough into a ball. Roll the balls in the sifted powdered sugar, and place on the sheet pan at least 2-inches apart.

Bake for 13 to14 minutes, until the surface of the cookies have cracked and puffed up. The cookies will not be browned. Cool the cookies on a wire rack and serve.