Preheat the oven to 350° F.
In the bowl of a hand or stand mixer fitted with the paddle attachment add the 1 cup unsalted butter and 2 cups of sugar. Mix on low- medium speed until light pale and fluffy looking. About 1 minute. Slowly add in the 1/4 cup oil and continue mixing until combined about 30 seconds.
Add in the eggs one at a time on low speed. When they are fully mixed in add the 1 tbsp vanilla, the 1 teaspoon white vinegar, and the 1 1/4 tbsp red food coloring. Mix until combined then scrape down the sides of the bowl with a spatula to make sure all the food coloring is mixed in.
In a medium sized bowl or on a large piece of parchment paper, combine the 2 1/2 cups flour, 1/4 cup cocoa, 1/2 tsp baking soda, and 1/2 tsp kosher salt.
In a measuring cup, measure out 3/4 cup buttermilk and set aside.
Turn the mixer on low and slowly add in 1/3 of the dry mixture. Mix for 30 seconds, then add in 1/2 the buttermilk. When combined add the next 1/3rd dry ingredients followed by the last half of the buttermilk. End with the last 1/3rd of the flour.
Heavily spray a bundt pan with baking spray, fill with the batter and bake for 55-60 mins. The cake is done when the sides start to pull from the edges of the pan or when a toothpick inserted comes out clean.
Let the cake cool for ten minutes, then invert onto a wire rack to cool completely.