Preheat the oven to 350°F. Thoroughly spray bundt pan with cooking spray.

In a medium bowl, whisk together the all-purpose flour, baking soda, and salt; set aside.

In a large bowl, using an electric mixer on medium speed, combine butter and sugar until creamy.

Add the vegetable oil, unsweetened cocoa powder, vanilla extract, food gel, and eggs, mixing until well combined.

Gradually add half of the dry ingredients, the wet ingredients, followed by buttermilk and vinegar.

Add the remaining flour mixture to the batter and mix until well combined.

Pour the cake batter into the prepared pan and bake for 50 to 60 minutes, until a skewer inserted into the center comes out clean.

Remove the bundt cake from the oven and cool on a wire rack for 15 minutes.

Remove the cake from the pan by placing the wire rack on top of the baked cake and flipping it over to gently release cake from pan using a flexible spatula if necessary to loosen the cake from on the sides of the pan.

Let the cake cool completely before finishing with frosting.

In a large bowl using an electric mixer on medium speed, whip the butter, cream cheese, until a velvety consistency forms. If it appears too thick, adjust its consistency by incorporating a dash of milk, as necessary, until the desired level of creaminess is achieved.

Add the frosting to a piping bag, cut the tip to your desired size and pipe the ridges of the cake. Smooth some frosting on the inside hole of the cake.