Position a rack in the middle of the oven and heat the oven to 350°F. Generously butter and flour a 4-1/2 x 8-1/2-inch loaf pan (Pyrex is fine).
Sift the flour, baking powder and salt together into a medium bowl. In a large bowl, beat the butter and lemon zest with an electric mixer on medium speed until light and smooth, about 1 minute (if you're using a stand mixer, use the paddle attachment). Add the sugar, eggs, coriander, and mace; beat until smooth. Add half of the milk and beat until just blended (the batter may look curdled; that's fine). Reduce the speed to low, add the flour mixture in two batches, beating just until blended and scraping the bowl with a rubber spatula as needed. Add the remaining milk and mix on low just until blended. Stir in the caraway seeds with a rubber spatula. Transfer the mixture to the prepared pan and smooth the top with a rubber spatula.
Bake until a wooden pick inserted in the center comes out clean, 60 to 65 minutes. Let cool in the pan on a rack for 10 minutes. Run a table knife around the inside of the pan, invert the cake out of the pan, flip it right side up onto the rack, and let it cool completely. (The cake will keep, tightly wrapped, at room temperature for up to three days.) Use a serrated knife to slice (the slices are fragile, so take care not to make them too thin). Seve with lemon curd, if you like.