Preheat oven to 350. Lightly grease cookie sheets.
Whisk together flour, baking powder, baking soda, and salt in a medium bowl. In a large bowl, beat butter and sugar on medium speed until creamy; then beat in eggs, vanilla, lemon zest, and ricotta until blended.
Add flour mixture and beat until combined. Cover and chill at least an hour.
Shape dough into balls, and place on cookie sheets.
Bake 10 minutes, or until bottoms are light brown. cool for about 1 minute, then transfer cookies to a wire rack to cool.
While they cool, make glaze: Stir confectioners' sugar and lemon juice in small bowl until smooth. Drizzle evenly over each cookie. Garnish with sprinkles. Let stand until glaze is hardened.