Preheat the oven to 325°F. Butter a 9 inch by 5 inch loaf pan, line the bottom with parchment paper, and butter the paper.
Sift or whisk the flour, baking powder, and salt together into a medium bowl.
1 7/8 cup (8 ounces or 227 grams) cake flour, 1/2 teaspoon baking powder, 1/2 teaspoon salt
Cream the butter, sugar, and zest together until it is light in color and fluffy, about 5-7 minutes. Scrape down the bowl.
16 tablespoons (8 ounces or 227 grams) unsalted butter, softened, 1 cup plus 2 tablespoons (8 ounces or 227 grams) granulated sugar, zest of one small orange
Add the eggs one at a time and beat on medium for one minute between each addition, scraping down the bowl as necessary.
4 large eggs, room temperature
Add the vanilla and beat in.
1 teaspoon vanilla extract
Add the dry ingredients and mix in on low or stir in by hand just until mixed.
1 cup chocolate chips
Mix in the chocolate chips by hand.
Transfer the cake batter to the prepared loaf pan and give it a few thwacks on the countertop to even it out.
Bake for 65 to 70 minutes in the middle of the oven until the top is a light brown and a toothpick inserted into the cake comes out clean. You may need to test a few places to avoid hitting a chocolate chip!
Let the cake cool in the pan for 10 minutes before removing from the pan onto a rack. Let the cake cool for at least one hour before cutting.
Store at room temperature, well-wrapped, for up to one week.