Preheat the oven to 400°F. Lightly grease (or line with parchment paper) two baking sheets., To make the cookies: In a large mixing bowl, beat together the butter, salt, vanilla, and baking powder., Beat in the sugar, then the egg., Add the flour to the wet ingredients alternately with the milk, beginning and ending with the flour. Do this gently; there's no need to beat the batter., Using a spoon or a tablespoon cookie scoop, drop the dough onto the prepared cookie sheets. The balls of dough should be about 1 1/4" in diameter. Flatten each mound of dough to a circle about 1 1/2" across; wet your fingers or a knife, or grease the bottom of a drinking glass or measuring cup to do this. Leave 2"; to 2 1/2" between each cookie, for expansion., Bake the cookies for about 10 to 11 minutes, or until they're a mottled brown on the bottom (carefully tilt one up to look), but not colored on top. You may see the barest hint of browning around the edges, but these cookies are supposed to be soft and cake-like, so don't over-bake them. Remove the cookies from the oven, and let them cool right on the pan as you make the frosting., To make the icing: Place the chocolate chips, corn syrup, vanilla, and cream into a large microwave-safe bowl, or into a large saucepan., Heat the mixture until it's very hot; the cream will start to form bubbles. Remove from the heat, and stir until smooth., Beat in the confectioners' sugar and salt. Let the icing cool to lukewarm., Dip each cookie into the lukewarm icing; swirl the cookie around to really give it a good coating. Set the cookies back on the baking sheet., Spread the remaining icing evenly atop the cookies. If it's too soft and flows off the cookies, let it set a bit, until it's firmer. It'll feel like you're piling on a lot of icing; that's precisely the point!, Storage information: Allow the icing to set completely, then store the cookies airtight in a single layer. Keep at room temperature for several days; freeze for longer storage.