Preheat the oven to 350 degrees fahrenheit. Spray a 10-cup bundt pan well with pan spray, preferably with a pan spray that contains flour such as Baker’s Joy. If any spray pools in the bottom of the pan, blot it out with a paper towel.

Add the butter, oil, and sugar to the bowl of a stand mixer and beat on medium-high for 2-3 minutes, until pale and fluffy. Scrape down the sides and bottom of the bowl as needed to ensure everything is evenly incorporated.

Add the eggs and vanilla bean paste and mix until incorporated.

In a medium bowl, whisk together the flour, baking soda, baking powder, and salt. Whisk together the buttermilk and sour cream in a separate bowl.

Add the dry ingredients and buttermilk mixture to the wet ingredients alternating the two. Scrape down the sides and bottom of the bowl as needed, until completely combined.

Pour the batter into the prepared bundt pan and bake for 40-45 minutes, or until a toothpick comes out clean from the center.

When the cake is cooled, prepare the glaze by whisking the powdered sugar, milk, and vanilla together until smooth. Pour over the top of the cake, letting it drip down the sides. You may thin the glaze down by adding an additional tablespoon or two of milk if you prefer a thinner glaze.