Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).

Grease and flour a 5-inch loaf pan, or line with parchment paper.

In a large bowl, cream together the butter and sugar until light and fluffy using an electric mixer.

Add the eggs one at a time, whisking for about 2 minutes after each addition until well combined.

Mix in the sour cream and vanilla extract until smooth.

In a separate bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.

Pour the batter into the prepared loaf pan and smooth the top.

Bake for 50-60 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.