In a medium-sized bowl, sift together the flour, baking powder, and salt. Set aside.
In a stand mixer fitted with a paddle attachment, cream the butter and sugar together until fluffy. Add eggs, one at a time, until well incorporated.
Fold in the flour mixture and milk, stirring until mixture becomes a wet batter. Stir in raisins and lemon zest.
Pour batter into a loaf pan and bake for about 40 minutes, until a toothpick inserted in the center comes out clean.