These cookies are light and cakey. They will keep for about a week in a tightly covered container. Let the glazed cookies sit at room temperature before storing to give the glaze time to set. This will keep the cookies from sticking together. You will need to chill the dough before baking for at least 30 minutes or up to 24 hours.
Preheat oven to 350 degrees F / 176 degrees C. Line a cookie sheet with parchment paper, or lightly grease.
Beat butter with hand mixer until soft and light in color. Add sugar gradually and beat until all the sugar is incorporated and the mixture looks light.
Add the egg, lemon juice, and rind and continue beating until the ingredients are completely blended in. Stir in ricotta until evenly mixed.
In separate bowl, whisk together flour, cornstarch, baking powder, baking soda and salt. Add to the butter mixture and stir by hand until no streaks of flour are visible. Chill the mixture for at least 30 minutes or up to 24 hours.
Roll chilled dough into 1-inch / 2.5 cm balls. Place on prepared cookie sheet and bake for 12 minutes or until cookies are set and can be lifted from the pan. You can check them at 10 minutes to see if they are ready.
While the cookies are baking, prepare the glaze by mixing together the icing sugar and lemon juice until smooth. Remove baked cookies from cookie sheet and place on cooling rack. Brush the hot cookies lightly with glaze.
Continue with remaining cookie dough and glaze. Brush the cookies with glaze again after they have cooled. Let the glaze set before storing cookies in an airtight container.