In a medium bowl combine the flour, baking powder, and salt. Set aside.
In the large bowl combine the butter and the sugar. Using an electric mixer beat the butter and sugar until light and fluffy, about 3 minutes. Add the eggs, 1 at a time, beating until incorporated. Add the ricotta cheese, lemon juice, and lemon zest. Beat to combine. Stir in the dry ingredients.
Line 2 baking sheets with parchment paper. Spoon the dough (about 2 tablespoons for each cookie) onto the baking sheets. Bake for 15 minutes, until slightly golden at the edges. Remove from the oven and let the cookies rest on the baking sheet for 20 minutes.