Preheat oven to 325°F (163°C) and grease a Bundt pan. Beat unsalted butter and cream cheese until light and fluffy.

Gradually add granulated sugar and vegetable oil, mixing until pale and well combined. Incorporate eggs one at a time, scraping down the bowl.

In another bowl, sift together cake flour and salt. Gradually add to creamy batter, mixing until just combined. Stir in vanilla extract.

Divide batter into two bowls. To one, add cocoa powder, red food coloring, and hot water. Whisk until smooth. Leave the other half as vanilla base.

Scoop alternating dollops of the red velvet and vanilla batter into the Bundt pan. Use a skewer to gently swirl without fully mixing.

Bake in preheated oven for 75-80 minutes until a toothpick comes out clean. Cool for about 10 minutes before inverting onto a wire rack.

For the glaze, combine cream cheese, powdered sugar, milk, and vanilla extract. Whisk until smooth and pourable.

Once the cake is cool, pour the glaze over the top, allowing it to cascade down the sides.