1 3/4 cups (230 grams) cake flour, sifted
2 teaspoons baking powder
1/8 teaspoon salt
1 cup (226 grams) (2 sticks) unsalted butter, room temperature
1 cup (200 grams) superfine or castor sugar
4 large eggs, room temperature
2 teaspoons pure vanilla extract
Zest of a lemon or orange (optional)
Note: To make your own superfine sugar - place 1 cup (200 grams) granulated white sugar in the bowl of your food processor. Process until very fine, about 30 seconds
Preheat oven to 350 degrees F (177 degrees C) and place rack in center of oven. Butter or spray with a pan spray, a 9 x 5 x 3 inch (23 x 13 x 8 cm) loaf pan. Line the bottom of the pan with parchment paper and butter or spray the paper.
In a large bowl, sift together twice, the flour, baking powder, and salt.
In the bowl of your electric mixer, or with a hand mixer, beat the butter until creamy and smooth. Gradually add the sugar, beating continuously on medium-high speed until light and fluffy (this will take about 5 minutes). Scrape down the sides of the bowl as needed. After about five minutes the batter should be light in color and fluffy in texture. Then add the eggs, one at a time, mixing well after each addition. Scrape down the sides of the bowl as needed. You will notice that the batter will look curdled. Don't worry as the batter will come together again after you add the flour mixture. Add the vanilla and lemon zest, if using, and beat until incorporated.
Add the flour mixture and mix just until incorporated. Pour the batter into the prepared pan and smooth the top.
Bake for about 50 to 60 minutes or until the cake is golden brown and a toothpick inserted in the center comes out clean.
Remove the cake from the oven and place on a wire rack to cool for about 10 minutes. Remove the cake from the pan and cool completely. Serve warm or at room temperature
Will keep several days well wrapped or it can be frozen for a month.