Gluten Free Lemon Meltaway Cookies

For the cookies 1 1/2 cups (210 g) all purpose gluten free flour (I used Better Batter)

xanthan gum (omit if your blend already contains it)

cornstarch

baking powder

kosher salt

confectioners’ sugar

Finely grated zest of 1 lemon

unsalted butter, at room temperature

egg white, at room temperature

freshly-squeezed lemon juice, plus more as necessary

Granulated sugar, for dipping

For the glaze 1 cup (115 g) confectioners’ sugar

to 4 teaspoons freshly-squeezed lemon juice