Preheat the oven to 350°F. Lightly grease a loaf pan: either 9" x 5", or 8 1/2" x 4 1/2". The smaller pan will yield a higher-crowned loaf., In a medium-sized mixing bowl, beat together the butter, sugar, salt, vanilla, baking powder, espresso powder, cocoa, and Cake Enhancer to make a sandy, somewhat clumpy mixture. Don't worry; the eggs will smooth things out., Add the eggs one at a time, beating well after each addition. Scrape down the sides and bottom of the bowl midway through this process., Add half the flour to the bowl, beating at low speed to combine., Add all of the milk, beating at low speed to combine., Add the remaining flour, beating gently just until the batter is smooth., Pour the batter into the prepared pan., Bake the cake for 60 to 70 minutes, or until a toothpick inserted into the center comes out clean. The top may look a tiny bit damp; that's OK. If you have an instant-read thermometer, the center will register about 205°F, while just under the top will register about 195°F., Remove the cake from the oven, loosen the edges, wait 10 minutes, and turn it out of the pan onto a rack to cool., Store completely cooled cake well wrapped, at room temperature.