Begin by preheating the oven to 400°F (200°C). Line two baking sheets with parchment paper or lightly grease them.

For the cookie dough: In a sizable mixing bowl, cream together the butter, salt, vanilla extract, and baking powder.

Progressively incorporate the granulated sugar into the mixture, followed by the egg.

Gradually fold in the unbleached all-purpose flour and milk, starting and finishing with the flour. Ensure the ingredients are combined but refrain from overmixing.

Deposit the dough onto the prepared baking sheets in mounds, approximately 1 1/4" in diameter. Using a moistened tool or your fingertips, gently flatten each mound to form a 1 1/2" diameter circle. Leave a gap of approximately 2" to 2 1/2" between each cookie to account for expansion.

Bake in the preheated oven for approximately 10 to 11 minutes. The cookies should display a subtle browning on their undersides but remain pale on top. It is essential not to over-bake them to maintain their desired soft, cake-like texture. Upon completion of baking, set them aside on the pan to cool.

For the icing: In a large, heatproof bowl or a saucepan, combine the semisweet chocolate chips, light corn syrup, vanilla extract, and heavy cream.

Heat the aforementioned mixture until it is near boiling and begins to exhibit bubbles. Once achieved, remove from heat and stir until the mixture is homogeneous.

Gradually blend in the sifted confectioners' sugar and salt, ensuring a smooth consistency. Allow the icing to cool until it reaches a lukewarm temperature.

Once the icing has cooled sufficiently, submerge each cookie to coat it evenly with the icing, and then place them back on the baking sheet.

If any icing remains, apply an additional layer atop each cookie for a more generous coating. Should the icing be excessively fluid and not remain on the cookies, it is advisable to wait until it achieves a slightly firmer consistency before applying.

Upon completion of icing, allow ample time for it to set. For preservation, store the cookies in a single layer within an airtight container. Room temperature storage is appropriate for several days, but refrigeration or freezing is recommended for prolonged periods.