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

In a large bowl, cream together the butter and granulated sugar until light and fluffy.

Add ricotta cheese, eggs, vanilla extract, and lemon zest. Mix until thoroughly combined.

In a separate bowl, whisk together flour, baking powder, and salt. Gradually add dry ingredients to the wet mixture and mix until just combined.

Drop tablespoonfuls of dough onto the prepared baking sheets, spacing about 2 inches apart. Bake for 13-15 minutes or until cookies are set and lightly golden at the edges. Let cool completely.

For the glaze, whisk together powdered sugar, milk, and vanilla extract until smooth. Dip the tops of cooled cookies into the glaze and let set before serving.