Preheat oven to 170C.

In mixing bowl, sift flour, baking powder and salt. Set aside.

Cream butter with handheld of stand mixer until creamy (about 2 mins). Add sugar gradually, and continue beating for another few minutes.

Reduce speed to low and add eggs one at a time until incorporated.

Add the citrus zest and vanilla extract.

Add flour mixture in 3 additions, alternating with cream.

Pour into lined (or well greased) pound cake mold, or single or multiple loaf pan and bake for 60-until the cake turns brown and a toothpick comes out clean when inserted in the center. If using min loaf pans, the baking time is about 40 minutes, if one loaf, 60-70 minutes.