Adjust oven rack to lower middle, and pre-heat oven to 350 degrees.

Whisk dry ingredients in a large bowl: flour, baking powder, baking soda, and salt.

Combine buttermilk and vanilla extract in a bowl

Whisk eggs and yolk together in a small bowl.

Using the paddle attachment in a stand mixer, beat butter and sugar on medium-high speed until pale and fluffy, about three minutes.

Reduce speed to medium and slowly add about half the eggs. Mix for about 15 seconds, and add the remaining eggs. Reduce speed and scrape down the sides of the bowl.

With the speed on low, add flour mixture in 3 additions, alternating with buttermilk mixture in 2 additions. Scrape bowl as needed. Give batter a final stir by hand.

Prepare bundt pan with floured baking spray

Scrape batter in pan. Bake until top is golden brown about 45-50 minutes, and rotate once halfway through. A skewer should come out clean when inserted in center (no crumbs attached.)

Let cake and pan cool on a wire rack for 10 minutes. Finish by inverting cake onto wire rack.

Decorate as desired or serve with fruit.<br>

Using whisk attachment in a stand mixer, beat butter on medium high until smooth (20 seconds).

Add sugar and salt, and slowly increase speed to medium-low. After 45 seconds most of the sugar should be moistened.

Scrape the sides of the bowl down, and mix again for 15 seconds.

Scrape the sides of the bowl down, and add vanilla and heavy cream. Beat at medium speed until incorporated, about 10 seconds. Increase speed to medium-high and beat until light and fluffy (about 4 minutes). Scrape the bowl down once or twice.