At least 1 hour before baking, drain the ricotta. Line a small colander with cheesecloth, paper towel, or a clean kitchen towel, add the ricotta, and set it over a bowl in the refrigerator. Let excess liquid drip off. While the ricotta drains, let the butter and egg come to room temperature.
Add the flour, baking powder, and salt to a small bowl and stir to combine. Set aside.
Preheat the oven to 350°F. Line 2 baking sheets with parchment paper.
Add the softened butter and granulated sugar to a mixing bowl and beat for 1-2 minutes, until light and creamy.
Add the egg and mix until fully combined, scraping down the sides of the bowl.
Add the drained ricotta, lemon zest, and lemon juice, and mix again until the mixture looks smooth and creamy.
Add the flour mixture to the bowl in two additions, mixing on low or with a spatula just until you have a soft, sticky dough. Do not overmix.
Cover the bowl and refrigerate the dough for about 45 to 60 minutes, until it firms up and is easy to scoop.
Add powdered sugar for rolling to a small bowl. Use a small cookie scoop (about 1 Tablespoon) or a spoon to portion the chilled dough into 1 to 1 and 1/4 inch balls. Roll each ball between your hands to smooth it, then roll it in powdered sugar so it is fully coated. Place the coated dough balls on the prepared baking sheets, leaving a little space between each cookie.
Bake for about 11 to 13 minutes, or until the bottoms are lightly golden and the tops are set with small cracks. The cookies should still feel soft in the center. Let them cool on the baking sheet for 5 minutes, then move them to a wire rack to cool completely.
To make the lemon glaze, add the powdered sugar, 2 Tablespoons of lemon juice to a small bowl. Stir until smooth and thick. Add more lemon juice, a few drops at a time, as needed, until the glaze is thick but slowly pours off a spoon in a ribbon.
Set the cooled cookies on a wire rack over a sheet of parchment. Spoon a small amount of glaze on top of each cookie, letting it gently spread toward the edges but not completely cover the crackles.
Let the glaze dry at room temperature until it is set and no longer tacky. The texture improves as the glaze dries; it will lose any pasty feeling and become smooth and slightly firm on top while the cookies stay soft and tender inside.