Preheat the oven to 350 degrees F. Butter a loaf pan (9-inch by 5-inch) well. Optional if the loaf pan is not non-stick - after buttering, dust with flour and shake out any excess flour
Mix the candied or crystallized ginger into the sugar, preferably with a food processor.
In a large bowl, whisk together the eggs, sugar, and pinch of salt for about 1-2 minutes, until well blended. Add in the lemon and orange zest.
In a smaller bowl, whisk or sift together the flour and baking powder. Use a sifter or a strainer (so the dry ingredients do not clump) to add the flour/baking powder into the wet ingredients in three portions. Whisk the ingredients together after each addition only until barely combined.
Once the dry ingredients are added in, whisk the heavy cream into the batter. Then gently incorporate the melted and cooled butter, using a rubber spatula rather than the whisk.
Using the spatula, put the matter into the loaf pan and bake for about 60 minutes, until a toothpick comes out clean. The cake should create a significant hump or crown as it bakes. After removing it from the oven, let the cake rest in the pan on a wire rack for 15 minutes, then unmold it and continue to let it cool.
Like pound cakes, this citrus loaf cake will actually improve in taste after it rests for a day. It will stay moist for several days, well wrapped, at room temperature. You can also freeze it, well wrapped.