Preheat your oven to 350°F (175°C). Place a rack in the center of the oven for even heat distribution.

Prepare your loaf pan by generously buttering and flouring a 9×5-inch loaf pan, tapping out excess flour, OR spray thoroughly with baking spray. Set aside.

Whisk the dry ingredients together in a medium bowl-combine the flour, baking powder, and salt. Whisk well to distribute everything evenly. Set aside.

Cream the butter in the bowl of a stand mixer fitted with the whisk attachment (or use a large bowl with a hand mixer). Beat the softened butter on medium speed for 2 minutes until creamy and smooth.

Add the granulated sugar and beat on medium speed for another 2 minutes until the mixture is light, fluffy, and pale in color.

Add eggs one at a time, scraping down the bowl first. Beat well after each addition (about 20–30 seconds each). Scrape down the bowl as needed. Pro tip: crack each egg into a separate small bowl first to avoid shells.

Add the sour cream and vanilla extract. Mix on medium speed until fully incorporated, scraping the bowl again to ensure even mixing.

With the mixer on low speed, add the flour mixture gradually. Mix only until you no longer see streaks of flour-stop as soon as it’s almost combined to avoid a tough cake.

Give the batter a final gentle stir with a spatula by hand to make sure there are no pockets of flour or unmixed butter at the bottom.

Pour the batter into the prepared loaf pan and smooth the top with a spatula so it’s level. Optional: place a thin strip of cold butter down the center of the batter for a controlled decorative crack.

Bake at 350°F for 60–70 minutes, or until a skewer or cake tester inserted into the center comes out clean with just a few moist crumbs. If the top is browning too quickly, loosely tent with aluminum foil for the last 15 minutes.

Let the cake cool in the pan for 15–20 minutes, then carefully turn out onto a wire rack to cool completely before slicing.