Place oven rack in the middle of the oven and preheat to 350. Generously butter and flour 5x9 loaf pan.
In a medium bowl, sift together flour, baking powder and salt. In a large bowl, beat the butter and lemon zest on medium speed, until light and smooth. Add sugar, eggs, coriander and mace; beat until smooth. Add half the milk and beat just until blended (the batter will look curdled). Reduce the speed to low, add the flour mixture in 2 batches, beating just until blended and scraping the bowl as needed. Add the remaining milk and mix just until blended. Stir in caraway seed. Scrape the batter into prepared loaf pan; smooth the top.
Bake until a toothpick inserted in the center comes out clean, 60-65 minutes. Let cool in the pan on a rack for 10 minutes. Run a knife around the inside of the pan, flip it right side up onto the rack, and let it cool completely. Do not slice too thin. Serve with lemon curd.