From America's Test Kitchen.
1 1/2 c. cake flour (if you don't have cake flour, you can replace 1 c. cake flour with 7/8 c. flour + 2 T. cornstarch)
1 t. baking powder
1/2 t. salt
1 1/4 c. sugar
4 large eggs, at room temp
1 1/2 t. vanilla extract
2 sticks unsalted butter, melted and hot
Adjust an oven rack to the middle position and heat the oven to 350 degrees. Lightly coat a 9 x 5" loaf pan with vegetable oil spray, then line the bottom with parchment paper. Whisk the flour, baking powder, and salt together in a large bowl and set aside.
Process the sugar, eggs, and vanilla in a food processor until combined, about 10 seconds. With the machine running, pour the melted butter through the feed tube in a steady stream, about 30 seconds. Pour the mixture into a large bowl.
Sift one-third of the flour mixture over the egg mixture and whisk in (a few streaks of flour should remain). Repeat twice more with the remaining flour mixture and continue to whisk the batter gently until most lumps are gone (do not overmix).
Pour the batter into the prepared pan and smooth the top. Wipe any drops of batter off the sides of the pan. Bake until a wooden skewer inverted into the center of the cake comes out with a few crumbs attached, 50-60 minutes, rotating the pan halfway through baking.
Let the cake cool in the pan for 10 minutes, then flip out onto a wire rack. Turn the cake right-side up, remove the parchment, and let cool to room temp, about 3 hours.