Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large bowl, whisk together the drained ricotta cheese, granulated sugar, egg, vanilla extract, lemon zest, and lemon juice until smooth.
In a separate medium bowl, whisk together the gluten-free flour blend, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Do not overmix. The dough will be soft.
Drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Bake for 12 to 15 minutes, or until the edges are lightly golden and the centers look set.
Remove cookies from the oven and let them cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.
While the cookies cool, prepare the glaze: Whisk the powdered sugar and 2 tablespoons of lemon juice together until smooth. Add more lemon juice, a few drops at a time, if the glaze is too thick.
Once cookies are fully cool, drizzle or dip the tops into the glaze. Let the glaze set before serving.
Notes
Drain the ricotta cheese in a fine-mesh sieve lined with cheesecloth or a coffee filter for at least 30 minutes to remove excess moisture. This prevents overly flat cookies.
If your gluten-free flour blend does not contain xanthan gum, add 1/2 teaspoon to the dry ingredients.
These cookies store well in an airtight container at room temperature for up to 3 days.