**Preheat the oven** Preheat your oven to 325°F (165°C). Grease and flour a 9x5-inch loaf pan or line it with parchment paper.
**Cream butter and sugar** In a large bowl, beat the softened butter and sugar on medium speed until light and fluffy, about 2–3 minutes.
**Add eggs and flavoring** Beat in the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.
**Combine dry ingredients** In a separate bowl, whisk together flour, baking powder (if using), and salt.
**Form the batter** Gradually add the dry mixture to the creamed butter mixture on low speed, mixing just until no streaks of flour remain. Avoid overmixing to maintain a tender crumb.
**Bake** Pour the batter into the prepared pan, smoothing the top. Bake for 60–70 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. If the top browns too quickly, loosely cover with foil during the last 10–15 minutes.
**Cool** Let the cake rest in the pan for 10 minutes before turning it out onto a cooling rack. Cool completely before slicing.