In a large bowl, stir together the blanched almond flour and baking powder. Set this dry mixture aside.

Place the softened cream cheese and butter in a mixing bowl. Beat with a stand mixer or hand mixer on medium speed until the mixture is smooth and fully blended.

Add the 1/2 cup powdered low-carb sweetener to the cream cheese mixture. Continue beating on medium speed for about 5 minutes, until the mixture becomes light and fluffy.

Mix in the egg, lemon flavoring, lemon zest, and lemon juice. Beat until well incorporated, scraping down the sides of the bowl as needed.

Reduce the mixer speed to low and gradually add the almond flour mixture. Mix just until a cohesive dough forms.

Cover the dough tightly with plastic wrap and refrigerate for at least 2 hours or overnight. For a quicker option, place the covered dough in the freezer for 25 minutes.

Preheat the oven to 350°F (177°C). Line two baking sheets with parchment paper or silicone baking mats.

Remove the chilled dough and portion it using a medium cookie scoop, about 2 tablespoons each. Roll each portion into a ball and arrange them on the prepared baking sheets, leaving at least 2 inches between each cookie.

Bake for 12 to 16 minutes, or until the bottoms begin to turn lightly golden. Let the cookies cool completely on the baking sheets before moving them.

While the cookies cool, prepare the icing by whisking together the powdered low-carb sweetener, lemon zest, heavy cream, and lemon juice in a medium bowl until smooth.

Transfer the cooled cookies to a wire rack. Brush or drizzle the lemon icing over the tops.