Add the flour mixture to the egg mixture and gently combine just until the flour disappears. Scrape the bowl a couple of times to ensure no streaks of butter are left unmixed.
Roll dough into tablespoon-size balls and place onto a cookie sheet covered with parchment paper or a silicone baking mat. (If dough is too soft to handle, chill for about 30 minutes.)
Bake for 2 minutes. Open the oven door and use a small cork, the small end of a round-handled wooden spoon, or your finger to make an indentation in the middle of each cookie. Bake another 8-9 minutes.
Working quickly, re-indent the center of each cookie. fill it with a half-teaspoon of ¼ cup lemon curd. Return to the oven for another 8-10 minutes until cookies start to brown on the edges.
Fill the indentation or cavity with a half teaspoon of lemon curd.
Return to the oven for another 8-10 minutes until cookies start to brown on the edges.
Allow the cookies to cool for about 15 minutes, then remove them to a wire rack. When completely cool, sprinkle them with¼ cup confectioners sugar or ice with frosting (see the notes below).
Notes
Powdered Sugar Frosting: Combine 1/2 cup of powdered sugar or confectioners' sugar with 1-2 teaspoons of milk. Stir together. Drizzle with a spoon or pour the icing into a small zippered plastic bag. Cut a small hole by snipping one corner of the bag. Squeeze the icing over the top of each cookie in any pattern you like.